Benzo diazepin-5-thiones

A careful and NMR study of 1,5-benzoxazine and 1,5-benzo-diazepine shows that these compounds exist in the amino-thione forms 55 and 56, respectively. Compound 55 displays a solvent-dependent amino/imino tautomerism (92MRC673).Tricyclic compounds 57, analogous to the bicyclics discussed above have been described they exist in the tautomeric form shown below (87BSB399,92BSB995,96BSB345). 

The identification of the HIV-1-specific non-nucleoside reverse transcriptase inhibitors (NNRTIs) as a separate class of HIV inhibitors was heralded by the discovery of the tetrahydroimidazo[4,5,1 -// .][ 1,4]benzo-diazepin-2(l //)-onc and -thione (TIBO) derivatives (Fig. 7) [58,59] and 1 -(2-hydroxyethoxymethyl)-6-(phenylthio)thymine (HEPT) derivatives (Fig. 8) [60,61]. The first TIBO derivatives (R82150, R82913) were the first NNRTIs [58] postulated to act as inhibitors of HIV-1 RT [59], For the HEPT derivatives it became evident that they also interact specifically with HIV-1 RT after a number of derivatives (i.e., E-EPU, E-EBU, and E-EBU-dM) had been synthesized that were more active than HEPT itself [62,63]. Following HEPT and TIBO, several other compounds, i.e., nevirapine, pyridinone, and bis(heteroaryl)piperazine (BHAP), were... 

Substituents, such as OH, SH, and NHj, can also participate in tautomeric equilibria, for example compare (13) with (14)-(16). The tautomerism of l,2-diazepin-4-ones has been thoroughly investigated by Moore et al. and the two keto tautomers (11) and (12) found to predominate in an equilibrium ratio of ca. 8 1, respectively (Equation (1)) <68JA1369, 73JOC2939>. 5 f-2,3-Benzo-diazepin-l-ones and benzodiazepine-1-thiones have also been established to exist in their oxo and thiono tautomeric forms <70BSF2237>. 

The first representative of the [l,2,4]triazino[5,6-fc]diazepin-8-ones 583 was obtained by reaction of 6-amino-3-(p-tolyl)[l, 2,4]triazin-5(2//)-thione 581 with 2//-1,3-oxazine-2,6(3//)-dione [85LA(3)640]. The benzo analogue [l,2,4]triazino[5,6-b][l,4]benzodiazepinones 582 were similarly obtained by reaction of 581 with isatoic anhydride. 

N-Alkyl isoindolo[2,l-fc][2,4]benzodiazepines 190 (R = alkyl. Scheme 38, Section 3.1.1.2) are synthesized by an intramolecular N-acyliminium ion-amide reaction (1997TL2985, 1998T1497). Isothiocyanates 23 undergo under basic conditions in DMF ring closure by an intramolecular substitution between N1 of the pyrrole ring and isothiocyanate group to afford benzo[/]pyrrolo[l,2-c] [l,3]diazepine-5-thiones 25 (Scheme 2, Section 2.1.1.1 (2005BMCL3220)). 

The reaction of 4-halogenated Ai-substituted 2(l/f)-pyridone 86 with o-phenylenediamines 87 gave the tricyclic benzo[fr][l,4]diazepine-2-thione-containing structure 88 <07JOC9259>. 

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