Tetrahydro-1,3-thiazines

Quantitation of the oral bronehodilator 2,5-diethyl-7-(tetrahydro-l,4-thiazin-4-yl)-l,2,4-triazolo[l,5-c]pyrimidine (R-836) (195) in plasma and urine of humans and experimental animals utilized reversed-phase HPLC and UV deteetion (88MI1). 

Chemical Name 2-(4-Chlorophenyl)tetrahydro-3-methyl-4H-1,3-thiazin-4-one 1,1-dioxide Common Name Chloromethazanone Structural Formula ... 

Dihydro-4H-l,3-thiazine werden durch Natriumboranat bei 0-10° in schwach sau-rer athanolischer Losung zu den Tetrahydro-1,3-thiazinen reduziert (vgl. S. 348)2 z.B. ... 

Thiazolidine, 2,5-Dihydro- 1,3-thiazole, Tetrahydro-l,3-thiazine und 5,6-Dihydro- 1,3-thiazine werden durch Lithiumalanat6,7 und meist auch durch Natriumboranat7 zu den (w-Mercapto-aminen aufgespalten. 1,3-Thiazolidine lassen sich mit einem Lithi-umalanat-OberschuB ahnlich den 4,5-Dihydro-1,3-oxathiolanen zu Athylaminen wei-terreduzieren7,8 ... 

A potential insecticide that is a derivative of tetrahydro-l,3-thiazine undergoes a number of reactions resulting in some 43 products of which the dimeric azo compound is the principal one in aqueous solutions (Figure 1.6) (Kleier et al. 1985). 

The reaction of tetrahydro-l,3-thiazine-2-thione and diethyl 2-chloro-malonate in the presence of triethylamine in boiling methylene chloride for 1.5 hr gave tetrahydro-1,3-thiazin-2-ylidenemalonate (508) in 33% yield via 507 through Eschenmoser sulfur elimination, together with traces of the mesoionic derivative (509) [77JCS(P 1) 1107]. In a similar reaction, diethyl 2-bromomalonate afforded the mesoionic compound (509) in 80% yield. Tetrahydro-l,3-thiazin-2-ylidenemalonate (508) was also obtained in 42% yield from 509 by irradiation in the presence of tributylphosphine in ethanol for 15 hr under argon [77JCS(P1)1107]. 

The exocyclic double bond of (tetrahydro-l,3-thiazin-2-ylidene)malo-nate (527) was saturated by reduction with Hg/Al in methanol at ambient... 

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