ID: 803351

[5-(trifluoromethyl)-1,3-benzoxazol-2-yl]methanamine			$$$$
M. F.	C9H7F3N2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20015 Database Data ID
M. W.	216.1598896
CAS
Similarity	N/A

ID: 803352

(5,6-difluoro-1,3-benzoxazol-2-yl)methanamine			$$$$
M. F.	C8H6F2N2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20016 Database Data ID
M. W.	184.1428464
CAS
Similarity	N/A

ID: 803353

(6-methyl-1,3-benzoxazol-2-yl)methanamine			$$$$
M. F.	C9H10N2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20017 Database Data ID
M. W.	162.1885
CAS
Similarity	N/A

ID: 803354

(7-fluoro-1,3-benzoxazol-2-yl)methanamine			$$$$
M. F.	C8H7FN2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20018 Database Data ID
M. W.	166.1523832
CAS
Similarity	N/A

ID: 803355

(7-bromo-1,3-benzoxazol-2-yl)methanamine			$$$$
M. F.	C8H7BrN2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20019 Database Data ID
M. W.	227.05798
CAS
Similarity	N/A

ID: 803356

2-(aminomethyl)-1,3-benzoxazole-7-carbonitrile			$$$$
M. F.	C9H7N3O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20020 Database Data ID
M. W.	173.17138
CAS
Similarity	N/A

ID: 803357

2-(aminomethyl)-1,3-benzoxazole-6-carbonitrile			$$$$
M. F.	C9H7N3O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20021 Database Data ID
M. W.	173.17138
CAS
Similarity	N/A

ID: 803358

6-bromo-2-(chloromethyl)-1,3-benzoxazole			$$$$
M. F.	C8H5BrClNO	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20023 Database Data ID
M. W.	246.4884
CAS
Similarity	N/A

ID: 803359

2-(chloromethyl)-6-methoxy-1,3-benzoxazole			$$$$
M. F.	C9H8ClNO2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20024 Database Data ID
M. W.	197.61832
CAS
Similarity	N/A

ID: 803360

2-(chloromethyl)-6-(trifluoromethyl)-1,3-benzoxazole			$$$$
M. F.	C9H5ClF3NO	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20025 Database Data ID
M. W.	235.5903096
CAS
Similarity	N/A

ID: 803361

2-(chloromethyl)-5,6-difluoro-1,3-benzoxazole			$$$$
M. F.	C8H4ClF2NO	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20027 Database Data ID
M. W.	203.5732664
CAS
Similarity	N/A

ID: 803362

2-(chloromethyl)-7-fluoro-1,3-benzoxazole			$$$$
M. F.	C8H5ClFNO	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20028 Database Data ID
M. W.	185.5828032
CAS
Similarity	N/A

ID: 803363

2-(chloromethyl)-4-fluoro-1,3-benzoxazole			$$$$
M. F.	C8H5ClFNO	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20029 Database Data ID
M. W.	185.5828032
CAS
Similarity	N/A

ID: 803364

7-bromo-2-(chloromethyl)-1,3-benzoxazole			$$$$
M. F.	C8H5BrClNO	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20030 Database Data ID
M. W.	246.4884
CAS
Similarity	N/A

ID: 803365

2-(chloromethyl)-1,3-benzoxazole-7-carbonitrile			$$$$
M. F.	C9H5ClN2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20031 Database Data ID
M. W.	192.6018
CAS
Similarity	N/A

ID: 803366

2-(chloromethyl)-1,3-benzoxazole-6-carbonitrile			$$$$
M. F.	C9H5ClN2O	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20032 Database Data ID
M. W.	192.6018
CAS
Similarity	N/A

ID: 803367

(1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-imidazol-5-yl)boronic acid			$$$$
M. F.	C9H19BN2O3Si	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20033 Database Data ID
M. W.	242.15526
CAS
Similarity	N/A

ID: 803368

[2-(ethoxycarbonyl)-1-methyl-1H-imidazol-5-yl]boronic acid			$$$$
M. F.	C7H11BN2O4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20034 Database Data ID
M. W.	197.98424
CAS
Similarity	N/A

ID: 803369

(1-methyl-1H-imidazol-5-yl)boronic acid			$$$$
M. F.	C4H7BN2O2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20035 Database Data ID
M. W.	125.92158
CAS	849062-28-8
Similarity	N/A

ID: 803370

[1-(triphenylmethyl)-1H-imidazol-4-yl]boronic acid			$$$$
M. F.	C22H19BN2O2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20036 Database Data ID
M. W.	354.20946
CAS
Similarity	N/A

ID: 803371

(1H-imidazol-4-yl)boronic acid			$$$$
M. F.	C3H5BN2O2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20037 Database Data ID
M. W.	111.895
CAS	943138-65-6
Similarity	N/A

ID: 803372

(1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-imidazol-4-yl)boronic acid			$$$$
M. F.	C9H19BN2O3Si	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20038 Database Data ID
M. W.	242.15526
CAS
Similarity	N/A

ID: 803373

[5-(ethoxycarbonyl)furan-2-yl]boronic acid			$$$$
M. F.	C7H9BO5	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20039 Database Data ID
M. W.	183.95436
CAS	1150114-44-5
Similarity	N/A

ID: 803374

[1-(triphenylmethyl)-1H-1,2,3-benzotriazol-5-yl]boronic acid			$$$$
M. F.	C25H20BN3O2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20041 Database Data ID
M. W.	405.2562
CAS
Similarity	N/A

ID: 803375

(2-cyanopyridin-4-yl)boronic acid			$$$$
M. F.	C6H5BN2O2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20042 Database Data ID
M. W.	147.9271
CAS	903513-60-0
Similarity	N/A

ID: 803376

[2-(cyanomethyl)phenyl]boronic acid			$$$$
M. F.	C8H8BNO2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20044 Database Data ID
M. W.	160.96562
CAS	16538-46-8
Similarity	N/A

ID: 803377

[2-(ethoxycarbonyl)pyridin-4-yl]boronic acid			$$$$
M. F.	C8H10BNO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20045 Database Data ID
M. W.	194.9803
CAS	794461-69-1
Similarity	N/A

ID: 803378

(1,3-oxazol-5-yl)boronic acid			$$$$
M. F.	C3H4BNO3	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20046 Database Data ID
M. W.	112.87976
CAS	808126-65-0
Similarity	N/A

ID: 803379

(2-hydroxyquinolin-3-yl)boronic acid			$$$$
M. F.	C9H8BNO3	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20047 Database Data ID
M. W.	188.97572
CAS	1101864-58-7
Similarity	N/A

ID: 803380

(2,3-dimethoxypyridin-4-yl)boronic acid			$$$$
M. F.	C7H10BNO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20048 Database Data ID
M. W.	182.9696
CAS	1031438-93-3
Similarity	N/A

ID: 803381

(3-chloro-5-methoxypyridin-4-yl)boronic acid			$$$$
M. F.	C6H7BClNO3	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20049 Database Data ID
M. W.	187.38868
CAS
Similarity	N/A

ID: 803382

3-(dihydroxyboranyl)pyridine-4-carboxylic acid			$$$$
M. F.	C6H6BNO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20050 Database Data ID
M. W.	166.92714
CAS	1072946-05-4
Similarity	N/A

ID: 803383

4-(dihydroxyboranyl)pyridine-3-carboxylic acid			$$$$
M. F.	C6H6BNO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20051 Database Data ID
M. W.	166.92714
CAS
Similarity	N/A

ID: 803384

[3-(benzyloxy)-4-methoxyphenyl]boronic acid			$$$$
M. F.	C14H15BO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20052 Database Data ID
M. W.	258.0775
CAS	243990-54-7
Similarity	N/A

ID: 803385

[2-(benzyloxy)-4-methoxyphenyl]boronic acid			$$$$
M. F.	C14H15BO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20053 Database Data ID
M. W.	258.0775
CAS	183474-19-3
Similarity	N/A

ID: 803386

[4-methoxy-2-(methoxymethoxy)phenyl]boronic acid			$$$$
M. F.	C9H13BO5	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20054 Database Data ID
M. W.	212.00752
CAS	183474-23-9
Similarity	N/A

ID: 803387

(4-cyano-3-methoxyphenyl)boronic acid			$$$$
M. F.	C8H8BNO3	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20055 Database Data ID
M. W.	176.96502
CAS	677777-45-6
Similarity	N/A

ID: 803388

(4-chloro-2-cyanophenyl)boronic acid			$$$$
M. F.	C7H5BClNO2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20056 Database Data ID
M. W.	181.3841
CAS	819070-53-6
Similarity	N/A

ID: 803389

(3-bromo-5-formylphenyl)boronic acid			$$$$
M. F.	C7H6BBrO3	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20057 Database Data ID
M. W.	228.83574
CAS	157866-06-3
Similarity	N/A

ID: 803390

(5-acetylpyridin-3-yl)boronic acid			$$$$
M. F.	C7H8BNO3	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20058 Database Data ID
M. W.	164.95432
CAS	1033745-21-9
Similarity	N/A

ID: 803391

[3-(trifluoromethyl)-1-(triphenylmethyl)-1H-pyrazol-4-yl]boronic acid			$$$$
M. F.	C23H18BF3N2O2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20059 Database Data ID
M. W.	422.2074296
CAS	474706-58-6
Similarity	N/A

ID: 803392

(5-chloro-2-nitrophenyl)boronic acid			$$$$
M. F.	C6H5BClNO4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20060 Database Data ID
M. W.	201.3722
CAS	532924-25-7
Similarity	N/A

ID: 803393

4-(dihydroxyboranyl)-2-nitrobenzoic acid			$$$$
M. F.	C7H6BNO6	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20061 Database Data ID
M. W.	210.93664
CAS	80500-28-3
Similarity	N/A

ID: 803394

(2-methoxy-5-nitrophenyl)boronic acid			$$$$
M. F.	C7H8BNO5	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20062 Database Data ID
M. W.	196.95312
CAS	677746-35-9
Similarity	N/A

ID: 803395

(4-{4-[(tert-butoxy)carbonyl]piperazin-1-yl}phenyl)boronic acid			$$$$
M. F.	C15H23BN2O4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20063 Database Data ID
M. W.	306.16512
CAS	457613-78-4
Similarity	N/A

ID: 803396

(3-{4-[(tert-butoxy)carbonyl]piperazin-1-yl}phenyl)boronic acid			$$$$
M. F.	C15H23BN2O4	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20064 Database Data ID
M. W.	306.16512
CAS
Similarity	N/A

ID: 803397

4-(dihydroxyboranyl)-3-methoxybenzoic acid			$$$$
M. F.	C8H9BO5	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20065 Database Data ID
M. W.	195.96506
CAS	741699-09-2
Similarity	N/A

ID: 803398

(2-cyano-3-fluorophenyl)boronic acid			$$$$
M. F.	C7H5BFNO2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20066 Database Data ID
M. W.	164.9295032
CAS	1218993-03-3
Similarity	N/A

ID: 803399

(3-bromo-2-cyanophenyl)boronic acid			$$$$
M. F.	C7H5BBrNO2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20069 Database Data ID
M. W.	225.8351
CAS	1032231-30-3
Similarity	N/A

ID: 803400

(5-chloro-2-cyanophenyl)boronic acid			$$$$
M. F.	C7H5BClNO2	Custom Synthesis Information This compound is available through custom synthesis, please feel free to contact us for a quote. Email: info@chembase.cn Suppliers Catalog Number A&J Pharmtech AJA-O20070 Database Data ID
M. W.	181.3841
CAS	1072946-52-1
Similarity	N/A

• ID:803351

  

  [5-(trifluoromethyl)-1,3-benzoxazol-2-yl]methanamine

• ID:803352

  

  (5,6-difluoro-1,3-benzoxazol-2-yl)methanamine

• ID:803353

  

  (6-methyl-1,3-benzoxazol-2-yl)methanamine

• ID:803354

  

  (7-fluoro-1,3-benzoxazol-2-yl)methanamine

• ID:803355

  

  (7-bromo-1,3-benzoxazol-2-yl)methanamine

• ID:803356

  

  2-(aminomethyl)-1,3-benzoxazole-7-carbonitrile

• ID:803357

  

  2-(aminomethyl)-1,3-benzoxazole-6-carbonitrile

• ID:803358

  

  6-bromo-2-(chloromethyl)-1,3-benzoxazole

• ID:803359

  

  2-(chloromethyl)-6-methoxy-1,3-benzoxazole

• ID:803360

  

  2-(chloromethyl)-6-(trifluoromethyl)-1,3-benzoxazole

• ID:803361

  

  2-(chloromethyl)-5,6-difluoro-1,3-benzoxazole

• ID:803362

  

  2-(chloromethyl)-7-fluoro-1,3-benzoxazole

• ID:803363

  

  2-(chloromethyl)-4-fluoro-1,3-benzoxazole

• ID:803364

  

  7-bromo-2-(chloromethyl)-1,3-benzoxazole

• ID:803365

  

  2-(chloromethyl)-1,3-benzoxazole-7-carbonitrile

• ID:803366

  

  2-(chloromethyl)-1,3-benzoxazole-6-carbonitrile

• ID:803367

  

  (1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-imidazol-5-yl)boronic acid

• ID:803368

  

  [2-(ethoxycarbonyl)-1-methyl-1H-imidazol-5-yl]boronic acid

• ID:803369

  

  (1-methyl-1H-imidazol-5-yl)boronic acid

• ID:803370

  

  [1-(triphenylmethyl)-1H-imidazol-4-yl]boronic acid

• ID:803371

  

  (1H-imidazol-4-yl)boronic acid

• ID:803372

  

  (1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-imidazol-4-yl)boronic acid

• ID:803373

  

  [5-(ethoxycarbonyl)furan-2-yl]boronic acid

• ID:803374

  

  [1-(triphenylmethyl)-1H-1,2,3-benzotriazol-5-yl]boronic acid

• ID:803375

  

  (2-cyanopyridin-4-yl)boronic acid

• ID:803376

  

  [2-(cyanomethyl)phenyl]boronic acid

• ID:803377

  

  [2-(ethoxycarbonyl)pyridin-4-yl]boronic acid

• ID:803378

  

  (1,3-oxazol-5-yl)boronic acid

• ID:803379

  

  (2-hydroxyquinolin-3-yl)boronic acid

• ID:803380

  

  (2,3-dimethoxypyridin-4-yl)boronic acid

• ID:803381

  

  (3-chloro-5-methoxypyridin-4-yl)boronic acid

• ID:803382

  

  3-(dihydroxyboranyl)pyridine-4-carboxylic acid

• ID:803383

  

  4-(dihydroxyboranyl)pyridine-3-carboxylic acid

• ID:803384

  

  [3-(benzyloxy)-4-methoxyphenyl]boronic acid

• ID:803385

  

  [2-(benzyloxy)-4-methoxyphenyl]boronic acid

• ID:803386

  

  [4-methoxy-2-(methoxymethoxy)phenyl]boronic acid

• ID:803387

  

  (4-cyano-3-methoxyphenyl)boronic acid

• ID:803388

  

  (4-chloro-2-cyanophenyl)boronic acid

• ID:803389

  

  (3-bromo-5-formylphenyl)boronic acid

• ID:803390

  

  (5-acetylpyridin-3-yl)boronic acid

• ID:803391

  

  [3-(trifluoromethyl)-1-(triphenylmethyl)-1H-pyrazol-4-yl]boronic acid

• ID:803392

  

  (5-chloro-2-nitrophenyl)boronic acid

• ID:803393

  

  4-(dihydroxyboranyl)-2-nitrobenzoic acid

• ID:803394

  

  (2-methoxy-5-nitrophenyl)boronic acid

• ID:803395

  

  (4-{4-[(tert-butoxy)carbonyl]piperazin-1-yl}phenyl)boronic acid

• ID:803396

  

  (3-{4-[(tert-butoxy)carbonyl]piperazin-1-yl}phenyl)boronic acid

• ID:803397

  

  4-(dihydroxyboranyl)-3-methoxybenzoic acid

• ID:803398

  

  (2-cyano-3-fluorophenyl)boronic acid

• ID:803399

  

  (3-bromo-2-cyanophenyl)boronic acid

• ID:803400

  

  (5-chloro-2-cyanophenyl)boronic acid