N‐alkyl‐4‐chloro‐1H‐benzo[c][1,2]thiazine‐3‐carbaldehyde‐2,2‐dioxides—New functional benzothiazine derivatives

Abstract

A synthesis of N‐alkyl‐4‐chloro‐1H‐benzo[c][1,2]thiazine‐3‐carbaldehyde‐2,2‐dioxides is described. Reactivity of new β‐chloroaldehydes is investigated, a number of novel benzo[c][1,2]thiazine derivatives are synthesized and characterized using 1H, 13C‐NMR, MS and elemental analysis.

Updating the CSIC Reaction (2003–2020)

“…[42] Compounds of type III (Figure 2) are flexible and very versatile, as the carbonyl and methylene groups, as well as the benzothiazinone core offer opportunities for further development. [43] Table 4. CSICr of 3-amino-3-C-cyano-3-deoxy-1,2 : 5,6-di-O-isopropylidene-3-N-alkananesulfonyl-α-D-allofuranoses (52 a,b).…”

“…As shown in Scheme 38, an example of this strategy was reported by Popov et al [43] The synthetic sequence started with the reaction of 2-aminobenzoic acid ethyl ester (157) with methanesulfonyl chloride/Et 3 N in dry dioxane to provide 2methanesulfonylamino-benzoic acid ethyl ester (158). Next, Nalkylation of 158 with different alkyl halides, in DMF/K 2 CO 3 , gave the corresponding ethyl N-alkyl-methylsulfonylaminobenzoates 159 a-f, whose intramolecular CSICr with NaH in dry DMF afforded N-alkyl-1H-benzo [c] [1,2]thiazin-4one-2,2-dioxides 95 b,c,f-i in high yields.…”

“…Ahmad et al have described [56] novel pyrano[2,1] benzothiazine hybrids 167 (Scheme 41) designed by juxtaposition of biologically relevant pyran heterocycles, [80] and benzothiazines, such as pyroxicam. [81] Target ligands 167 were easily prepared in two steps starting from 159 precursors as shown in [43] Scheme 39. CSICr reported by Ogata et al [79] Scheme 40.…”

Heteroatom insertion into 3,4-dihydro-1H-quinolin-2-ones leads to potent and selective inhibitors of human and rat aldosterone synthase

“…The benzyl protected benzothiazinonedioxide 15b was synthesized according to a reaction sequence previously described for similar compounds by Volovenko et al [51] Suzuki coupling and subsequent reductive deprotection of the benzyl group provided compound 15.…”

On the functionalization of benzo[e][2,1]thiazine

“…In previous work [ 8 – 9 ] we reported the synthesis of some novel benzothiazines, in particular benzo[ e ][2,1]thiazine derivatives, the β-chloroaldehydes 1 and β-chloronitriles 2 ( Fig. 1 ); their chemistry was shown to be quite versatile.…”