Pyrrolobenzothiazepinones and pyrrolobenzoxazepinones: novel and specific non-nucleoside HIV-1 reverse transcriptase inhibitors with antiviral activity

Two novel classes of pyrrolobenzothiazepinones and pyrrolobenzoxazepinones were investigated as potential anti-AIDS drugs. These compounds were found to inhibit HIV-1 reverse transcriptase (RT) enzyme in vitro and to prevent HIV-1 cytopathogenicity in T4 lymphocytes, without appreciable activity on HIV-2 cytopathic effects, and against HBV as well as calfthymus DNA alpha-polymerase. Their potency is influenced by substituents at position 6 and on the fused aromatic ring. Specifically, small lipophilic substituents at C-6 were preferred, whereas substitutions on the benzo-fused ring were found to be detrimental to activity, with respect to the unsubstituted compounds. Modification of the pie-system at C-6 is well tolerated, although the replacement of the benzo-fused with a [2,3]naphtho-fused ring leads to a less active compound. Maximum potency and specificity is achieved with a phenyl and an ethyl group at position 6 of the pyrrolobenzoxazepinone system. In the enzymatic assay the oxazepinone derivative (+/-)-6-ethyl-6-phenylpyrrolo[2,1-d][1,5] benzoxazepin-7(6H)-one 16e (IC50 = 0.25 microM) was found to be more potent than nevirapine (IC50 = 0.5 microM), tested in the same experimental conditions using rC.dG as a template-primer. In cell culture assay benzoxazepine 16e was active against HIV-1, both wild type and AZT-sensitive, and HIV-1 (IIIB) strains, but not against HIV-2. In enzyme assay although 16e inhibited HIV-1 RT, it was inactive against the nevirapine-resistant recombinant RT Y181C at 50 microM. Molecular modeling studies suggest that these derivatives present a 3D pharmacophoric arrangement similar to that of other non-nucleoside inhibitors such as nevirapine.

A concerted study using binding measurements, X-ray structural data, and molecular modeling on the stereochemical features responsible for the affinity of 6-arylpyrrolo[2,1-d][1,5]benzothiazepines toward mitochondrial benzodiazepine receptors

The 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives have been recently proposed as a new class of ligands specific for the mitochondrial benzodiazepine receptor (Fiorini et al. J. Med. Chem. 1994, 37, 1427-1438) (Greco et al. J. Med. Chem. 1994, 37, 4100-4108). In this paper we report the X-ray crystallographic structures of three potent (1-3) and two inactive (4 and 5) previously described benzothiazepines, as well as binding affinity constants for two newly assayed analogs in which the acyloxy side chain was replaced by a methoxy group (6) or removed (7). Structure-affinity relationships and molecular mechanics calculations performed using crystal structures as references have led to a revised 3D pharmacophore model accounting for all the data available up until now. Interestingly, the hypothetical receptor-bound conformations of 1-3 display a considerable degree of similarity with their crystal geometries. Additional calculations have confirmed that the poor affinities of benzothiazepines bearing an aroyloxy group (4 and 5) should be ascribed to the steric and/or electronic features of the side chain aryl moieties rather than to unfavorable conformational properties.

Pyrrolo[2,1-c][1,4]benzothiazines: synthesis, structure-activity relationships, molecular modeling studies, and cardiovascular activity

The synthesis and pharmacological evaluation of a series of pyrrolo[1,4]benzothiazine derivatives are described. These compounds, related to diltiazem, have been shown to be representative of a novel series of calcium channel antagonists. The IC50S for inhibition of [3H]nitrendipine binding calculated by radioreceptor assay on rat cortex and rat heart homogenates showed that some of the described compounds possess an affinity equal to or higher than those of the reference calcium antagonists verapamil and cis-(+)-diltiazem. Furthermore, the alteration of the benzothiazepinone system of diltiazem to the pyrrolo[1,4]benzothiazine system of the title compounds resulted in a clear-cut selectivity for cardiac over vascular tissue, as shown in functional studies. In fact comparison of calcium antagonist activity on guinea pig aorta strips with the negative inotropic activity, determined by using an isolated guinea pig left atrium, revealed that the compounds examined displayed higher selectivity than the reference standard, within a wide variation of data. A number of structure-activity relationship trends have been identified, and possible explanation is advanced in order to account for the observed differences in selectivity. Prerequisite for in vitro calcium channel-blocking activity is the presence of two pharmacophores, namely, the substitution at C-4 and the substitution on the pyrrole ring. Two of the tested compounds, 8b and 28a, were identified as potent calcium antagonists selective for cardiac over vascular tissue.

A comparative molecular field analysis model for 6-arylpyrrolo[2,1-d] [1,5]benzothiazepines binding selectively to the mitochondrial benzodiazepine receptor

A series of 42 6-arylpyrrolo[2,1-d][1,5]benzothiazepines, which we have recently described as selective ligands of the mitochondrial benzodiazepine receptor (MBR) (Fiorini I.; et al. J. Med. Chem. 1994, 37, 1427-1438), have been investigated using the comparative molecular field analysis (CoMFA) approach. The resulting 3D-QSAR model rationalizes the steric and electronic factors which modulate affinity to the MBR with a cross-validation standard error of 0.648 pIC50 unit. A set of seven novel pyrrolobenzothiazepine congeners has successively been synthesized and tested. The CoMFA model forecasts the binding affinity values of these new compounds with a prediction standard error of 0.536.

Novel ligands specific for mitochondrial benzodiazepine receptors: 6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives. Synthesis, structure-activity relationships, and molecular modeling studies

A novel class of ligands specific for MBR receptors has been identified: 6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives. The majority of newly synthesized esters 37-64 as well as some intermediate ketones showed micro- or nanomolar affinity for [3H]PK 11195 binding inhibition. A SAR study on 42 compounds and a molecular modeling approach led to a preliminary structural selectivity profile: the 6,7-double bond, the carbamoyloxy, alcanoyloxy, and mesyloxy side chains at the 7-position, and the prospective chloro substitution at the 4-position seemed to be the most important structural features improving affinity. Therefore, 7-[(dimethylcarbamoyl)oxy]- and 7-acetoxy-4-chloro-6-phenylpyrrolo[2,1-d][1,5]benzothiazepine (43 and 57) were synthesized. With 7-[(dimethylcarbamoyl)oxy]-6-(p-methoxyphenyl)pyrrolo[2,1- d][1,5]benzothiazepine (65), these were the most promising compounds with IC50s of respectively 9, 8, and 9 nM, under conditions where PK 11195 had an IC50 of 2 nM.

Benzothiazine and benzothiazepine derivatives: synthesis and preliminary biological evaluation

Several tricyclic benzothiazines and benzothiazepines have been synthesized by different intramolecular cyclization reactions. Their functionalization led to biologically active compounds. Some stereochemical aspects as well as biological responses have been outlined.

Research on compounds with psychotropic activity. IX--Synthesis of 6-p-methoxyphenylpyrrolo[2,1-d][1,5]benzothiazepines and evaluation of their affinities for BDZ and GABA receptor subtypes

6-p-Methoxyphenylpyrrolo[2,1-d][1,5]benzothiazepin-7(6H)-one (IV), cis-7-acetoxy-6,7-dihydro-6-p-methoxyphenylpyrrolo[2,1-d] [1,5]benzothiazepine (V) and some significant 7-acyloxy-6-p-methoxyphenylpyrrolo[2,1-d][1,5]benzothiazepines (VI a-g) were synthesized and tested in vitro for inhibition of the specific binding of 3H-Flunitrazepam, 3H-PK 11195, 3H-Muscimol and 3H-(-)Baclofen to central and peripheral benzodiazepine, GABA-A and GABA-B receptors, respectively. The compounds (IV), VI a) and (VI c) were active on the peripheral benzodiazepine receptor; in particular (VI a) and (VI c) were very active. The compound (VI g) showed an affinity, even though scanty, for the central benzodiazepine receptor.

[Compounds with psychotropic activity. VIII. Synthesis and sedative activity of various 9-substituted derivatives of 5-phenylpyrrolo[2,1-d][1,5] benzothiazepine and cis-4,5-dihydro-4-hydroxy-5-phenylpyrrolo[2,1-d][1,5]benzothiazepine]

Syntheses of 9-chloro-, 9-trifluoromethyl- and 9-methoxy-5- phenylpyrrolo [2,1-d] [1,5] benzothiazepine [II a-c] and of cis-9-chloro- and cis-9-trifluoromethyl-4,5-dihydro-4-hydroxy-5- phenylpyrrolo [2,1-d] [1,5] benzothiazepine with the respective acetyl derivatives (III a-d), according to previously restated routes, are described. The sedative activity was tested against the anti-amphetamine activity in the rat. The 1-[5-trifluoromethyl-2-(alpha- hydroxycarbonylbenzyl ) thiophenyl + ++]-pyrrole ( NF34 ) and the pyrrolo [2,1-d] [1,5] benzothiazepine -5-carboxamide ( NF44 ) showed sedative activity similar to that of diazepam.

[Research on a compound with psychotropic activity. V - a new derivative of pyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide: synthesis and sedative activity]

The following compounds have been synthesized according to a previously tested route, of the 9-chloro-, 9-trifluoromethyl- and 9-methoxy-5-phenylpyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide (II a-c), 9-chloro- and 9-trifluoromethyl-5-p-nitrophenylpyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide (II d, e), 5-(4-pyridyl)pyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide (III) and 5-(3-pyridyl)pyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide (IVa) with the 9-chloro- and 9-trifluoromethyl- derivatives (IV b, c) are reported. The sedative action in the rat was tested against the motor activity induced by amphetamine. The 9-chloro-5(3-pyridyl)pyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide was particularly active and showed sedative action superior to that of diazepam. Marked sedative activity was observed with 9-methoxy-5-phenylpyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide (NF19) and 9-chloro-5-p-nitrophenylpyrrolo[2,1-d][1,5]benzothiazepin-6,6-dioxide (NF20).

[Studies on substances with antiblastic activity. IX. Anthramycin and analogs. IX. Synthesis of 7-methoxy-8-hydroxy-10,11-dihydro-5H-pyrrolo[2,1-c] [1,4] benzodiazepine and other compounds related to oxotomaymycin]

The synthesis of some pyrrolobenzodiazepine derivatives related to oxotomaymycin, an antibiotic recovered together with tomaymycin from fermentation broths of Streptomyces achromogenes var. tomaymycetics, is described. Reaction between 2-nitro-4-benzyloxy-5-methoxybenzylbromide and pyrrole-2-carboxyaldehyde afforded 1-(2-nitro-4-benzyloxy-5-methoxybenzyl)pyrrole-2-carboxyaldehyde. Catalytic reduction of this compound with hydrogen in the presence of Pd/C gave 10,11-dihydro-8-hydroxy-7-methoxy-5H-pyrrolo[2.1-c] [1,4]benzodiazepine. Amides obtained from condensation between 2-nitro-4-benzyloxy-5-methoxybenzoic acid chloride and proline or hydroxyproline were reduced catalytically to 2,3-dihydro-8-hydroxy-7-methoxy-1H-pyrrolo [2,1-c] [1,4]benzodiazepine-5,11 (10H, 11aH)-dione and its 2-hydroxyderivative respectively. The synthesis of 10,11-dihydro-8-hydroxy-9-methoxy-5-pyrrolo [2,1-c] [1,4]benzodiazepine is also reported.

[Research on nitrogen heterocyclic compounds. XI. - New synthesis of 3H-benz(e)indole and its derivatives]

Glutaconic esters bearing a 2-naphthylamino moiety and a carbethoxy group at the 4-position underwent thermal decomposition to give 1-carbethoxy-3H-benz[e]indole derivatives. Alkaline hydrolysis of 1-carbethoxy-3H-benz[e]indoles gave the corresponding 3H-benz[e]indoles by loss of the carboxylic group. By this method were synthesized the known 3H-benz[e5indole and the 7-methoxy-3H-benz[e]indole. Glutaconic esters used in this procedure were prepared by condensation of ethyl propiolate with the appropriate 2-naphthylaminomalonate ethyl ester in the presence of a catalytic amount of sodium ethylate.

[Research on substances with psychotropic activity. IV. Synthesis of 2,3-diphenyl-4-methyl-4H-1,4-benzothiazin-1,1-dioxide by thermal cyclization of N-(2-desylsolfonylphenyl) glycine]

Treatment of the ethyl ester of N-benzoyl-N-(2-benzylsolfonylphenyl)glycine with potassium in benzene gave, by rearrangement, N-(2-desylsolfonylphenyl)glycine, which via thermal intramolecular cyclization and simultaneous decarboxylation gave 2,3-diphenyl-4-methyl-4H-1,4-benzothiazin-1,1-dioxide. The structure of the latter compound was confirmed chemically by oxidising the known 2,3-diphenyl-4-methyl-4H-1,4-benzothiazine with hydrogen peroxide in formic acid and by I;R. and N.M,R; spectral data.