Benzo[b]thiophene-2-carboxylic acid

Synthesis and Antitubercular Activity of New Benzo[b]thiophenes.[Pubmed:27563398]

ACS Med Chem Lett. 2016 Jun 28;7(8):751-6.

In vitro and ex vivo efficacies of four series of Benzo[b]thiophene-2-carboxylic acid derivatives were studied against Mycobacterium tuberculosis H37Ra (MTB). Benzo[b]thiophenes were also tested in vitro against multidrug resistant Mycobacterium tuberculosis H37Ra (MDR-MTB), and 7b was found to be highly active against A- and D-MDR-MTB/MTB (MIC ranges 2.73-22.86 mug/mL). The activity of all benzo[b]thiophenes against M. bovis BCG (BCG) was also assessed grown under aerobic and under conditions of oxygen depletion. Compounds 8c and 8g showed significant activity with MICs of 0.60 and 0.61 mug/mL against dormant BCG. The low cytotoxicity and high selectivity index data against human cancer cell lines, HeLa, Panc-1, and THP-1 indicate the potential importance of the development of benzo[b]thiophene-based 1,3-diketones and flavones as lead candidates to treat mycobacterial infections. Molecular docking studies into the active site of DprE1 (Decaprenylphosphoryl-beta-d-ribose-2'-epimerase) enzyme revealed a similar binding mode to native ligand in the crystal structure thereby helping to understand the ligand-protein interactions and establish a structural basis for inhibition of MTB. In summary, its good activity in in vitro and ex vivo model, as well as its activity against multidrug-resistant M. tuberculosis H37Ra in a potentially latent state, makes 7b an attractive drug candidate for the therapy of tuberculosis.

Structure-activity relationships of 6-methyl-benzo[b]thiophene-2-carboxylic acid (1-[(S)-1-benzyl-4-[4-(tetrahydropyran-4-ylmethyl)piperazin-1-yl]butylcarbamoyl]c yclopentyl)amide, potent antagonist of the neurokinin-2 receptor.[Pubmed:20408549]

J Med Chem. 2010 May 27;53(10):4148-65.

As part of a project aimed at the identification of a series of small, orally available antagonists for the hNK(2) receptor, starting from one of our capped dipeptide libraries, we succeeded in the chemical optimization of the first identified leads, finally producing a class of molecules with significant activity in our animal model after iv administration. We herein report the results of further chemical modifications made to reduce the overall peptide character of this series and the consequent improvement of their in vivo antagonist activity. The present work identified 6-methylBenzo[b]thiophene-2-carboxylic acid (1-[(S)-1-benzyl-4-[4-(tetrahydropyran-4-ylmethyl)piperazin-1-yl]butylcarbamoyl]c yclopentyl)amide (10i), endowed with subnanomolar potency in all the in vitro tests and being highly potent and of long duration upon in vivo testing after both iv and id dosing.

Synthesis and pharmacological evaluation of 2-substituted benzo[b]thiophenes as anti-inflammatory and analgesic agents.[Pubmed:18433939]

Eur J Med Chem. 2009 Apr;44(4):1718-25.

An efficient method for trapping isocyanate 4, generated from the Curtius rearrangement, with ethyl alcohol to afford the carbamate 5 is reported. 5-NitroBenzo[b]thiophene-2-carboxylic acid 1 is converted to the corresponding hydrazide 2 by the reaction with hydrazine hydrate and then to the azide 3 with nitrous acid, followed by thermal rearrangement, cooling, and trapping in one pot reaction. The carbamate 5 is treated with hydrazine hydrate to afford the desired, Zileuton analogue, 4-(5-nitrobenzo[b]thiophene-2-yl)semicarbazide 6. Also the reactivity of hydrazide 2 towards some carboxyaldehydes and phenylisothiocyanate afforded the corresponding carbohydrazides 7, 8 and phenylthiosemicarbazide 9, respectively. Compounds 9, 2 and 6, respectively, were more potent as anti-inflammatory and anti-nociceptive agents.

MEN15596, a novel nonpeptide tachykinin NK2 receptor antagonist.[Pubmed:16979621]

Eur J Pharmacol. 2006 Nov 7;549(1-3):140-8.

The pharmacological profile of MEN15596 or (6-methyl-Benzo[b]thiophene-2-carboxylic acid [1-(2-phenyl-1R-{[1-(tetrahydropyran-4-ylmethyl)-piperidin-4-ylmethyl]-carbamoyl} -ethylcarbamoyl)-cyclopentyl]-amide), a novel potent and selective tachykinin NK2 receptor antagonist endowed with oral activity, is described. At the human recombinant tachykinin NK2 receptor, MEN15596 showed subnanomolar affinity (pKi 10.1) and potently antagonized (pKB 9.1) the neurokinin A-induced intracellular calcium release. MEN15596 selectivity for the tachykinin NK2 receptor was assessed by binding studies at the recombinant tachykinin NK1 (pKi 6.1) and NK3 (pKi 6.4) receptors, and at a number of 34 molecular targets including receptors, transporters and ion channels. In isolated smooth muscle preparations MEN15596 showed a marked species selectivity at the tachykinin NK2 receptor with the highest antagonist potency in guinea-pig colon, human and pig bladder (pKB 9.3, 9.2 and 8.8, respectively) whereas it was three orders of magnitude less potent in the rat and mouse urinary bladder (pKB 6.3 and 5.8, respectively). In agreement with binding experiments, MEN15596 showed low potency in blocking selective NK1 or NK3 receptor agonist-induced contractions of guinea-pig ileum preparations (pA2

Selective thromboxane synthetase inhibitors. 3. 1H-imidazol-1-yl-substituted benzo[b]furan-, benzo[b]thiophene-, and indole-2- and -3-carboxylic acids.[Pubmed:3746813]

J Med Chem. 1986 Sep;29(9):1637-43.

The preparation of a series of 1H-imidazol-1-yl-substituted benzo[b]furan-, benzo[b]thiophene-, and indolecarboxylic acids is described. Most of the compounds were potent inhibitors of TxA2 synthetase in vitro, and the distance between the imidazole and carboxylic acid groups was found to be important for optimal potency. The most potent compound in vivo was 6-(1H-imidazol-1-ylmethyl)-3-methylBenzo[b]thiophene-2-carboxylic acid (71), which, in conscious dogs, showed a similar profile of activity to that of dazoxiben (1).