Synthesis of a dithieno2,3-b:3prime;,2prime;-e1,4thiazine and of di-3-thienylamine

摘要

1234 J.C.S. Perkin ISynthesis of a Dithieno2,3-b :3',2'-e I ,4thiazine and of Di-3-thienyl-amineBy Cor J. Grol, Department of Pharmaceutical Chemistry, Ant. Deusinglaan 2, State University, Groningen,4-Acetyldithieno2,3-b;3'.2'-e 1,4 thiazine has been synthesized by direct sulphuration of N-acetyldi-3-thienylamine with sulphur dichloride. Hydrolysis of the latter amide afforded di-3-thienylamine, which wasnot present in the imino-form as shown by l H n.m.r. spectroscopy.The NetherlandsWE have previously described the preparation of thefirst dithienothiazine, as a result of our studies on thesynthesis of thiophen analogues of phenothiazines.AcCU~K2C03n i t robcntenc GN-@ NHAc/ ( 3 ) ( 2 ) ( 1 ) p2Acs s s( 5 1 ( 4 1Because of the length of this synthesis we have beensearching for a more direct way of preparing someadditional derivatives of this new heterocyclic system.t For details of Supplementary Publications see Notice to1 C.J . Grol and J. S. Faber, Rec. Trav. ckim., 1970, 89, 68.Authors No. 7 in J.C.S. Pevkin I, 1974, Index issue.R. R. Estes and P. Panzera, J . Amer. Chem. SOC., 1962, 74,863.The simplest way to the dithienothiazines seemed to besulphuration of an NN-dithienylacetamide or of thecorresponding dithienylamine, and we therefore in-vestigated the sulphuration of N-acetyldi-3-thienyl-amine, with two equivalent a-positions.with 3-acetamidothiophen (1),synthesized from thiophen-3-carboxamide by a Hof-mann rearrangement, and 3-bromothiophen (2) gavethe amide (3), which converted directly into the dithieno-thiazine (4) with sulphur dichloride in benzene.The dithienothiazine (4) was not hydrolysed to theunsubstituted thiazine by acid or base. Hydrolysis ofthe N-acet yldit hienylamine with ethanolic potassiumhydroxide gave the amine (5), vmX. 3400 crn-l, 6 5.7(NH), indicating that at room temperature it is notpresent in the imino-f~rm.~A coupling reactionEXPERIMENTALThe Experimental section is available as SupplementaryPublication No. SUP 21350 (4 pp.).?4/2469 Received, 26th November, 1974)3 E. Campaigne and P. A. Monroe, J . Amer. Chsm. SOC., 1964,4 A. R. Katrizky and J . M. Lagowski, Adv. Heterocyclic Chem.,76, 2447.1964, 2, ch. 1