With thiophosgene

In a first step, 2-naphthol is reacted with thiophosgene to give 2-naphthyl chlorothionofor-mate. 

Reaction of 2,6-dimethylaniline with thiophosgene produces isothiocyanate 171. When the latter is treated with 3-aminopropanol, thiourea 172 is formed, and this, when treated with hot concentrated hydrochloric acid, cyclizes to xylazine (173), an analgetic... 

The reaction of tetrazole 132 with thiophosgene leads to [l,2,4]triazolo[3,4+][l,3,4]thiadiazoles 49. The reaction involves the in situ generation of aryldiazomethanes by decomposition of the tetrazole, followed by two cycloadditions (Equation 38) <1999CPA215>. 

In contrast, when /f-D-mannopyranosylamine reacts with thiophosgene, only the cis bicyclic thionocarbamate is formed and the transient isothiocyanate cannot be detected (Scheme 4). The different behaviour of the cis and trans hydrindane-type systems can be explained by the strain in the ring fusion for a trans species. 

Amino-2-deoxy aldoses. The behaviour of O-unprotected sugars is exemplified in D-gluco series after basic hydrolysis of the starting 2-benzamidoglycoside followed by buffering the medium with carbon dioxide and treatment with thiophosgene, an intermediate isothiocyanate was obtained.320 However, NMR revealed a temperature-dependent equilibrium of this isothiocyanate with a trans-fused OZT (Scheme 5). 

A different approach involving cyanohydrin formation from the 3-keto sugar was also explored in the D-Fru series (Scheme 17). A mixture of epimeric cyanohydrins was quantitatively formed by reaction with sodium cyanide in methanol, albeit without stereoselectivity. Chromatographic separation of (R)- and (A)-isomers was straightforward and the former epimer was selected to exemplify the two-step transformation into an OZT. Reduction of this nitrile by lithium aluminum hydride led to the corresponding aminoalcohol, which was further condensed with thiophosgene to afford the (3i )-spiro-OZT in ca. 30% overall yield. Despite its shorter pathway, the cyanohydrin route to the OZT was not exploited further, mainly because of the disappointing yields in the last two steps. 

Symmetrical dialkyl and diaryl thioureas have been prepared in generally good yield (60-90%) from the reaction of the amine with thiophosgene, formed in situ from the catalysed reaction of carbon tetrachloride with sodium sulphide [5], Reaction with diamines yields cyclic ureas. 

Alternative precursors for the synthesis of NHCs are thiourea derivatives of type 3. The preparation of such thiones with a symmetrical substitution pattern is achieved by the reaction of a-hydroxyketones like 3-hydroxy-2-butanone with suitable 2-thiones (Fig. 3d) [31] or by reaction of a diamine with thiophosgene [32, 33]. Unsymmetrically substituted thiones 4 possessing a saturated heterocycle have also been described (Fig. 3e) [34, 35]. 

On the basis of the above-mentioned calculations it seems that coordination chemistry is a viable alternative to stabilize this heterocumulene. However, the experimental access to metal complexes containing the tricarbon monoxide ligand remains a challenge. Thus, to date, the coordination chemistry of C3O is confined to [Cr(=C=C=C=0)(C0)s] (89), obtained by treatment of [n-Bu4N] [CrI(CO)5] with the silver acetylide derived of sodium propiolate in the presence of Ag" (Scheme 28) [105]. Reaction of the presumed Tt-alkyne intermediate complex 88 with thiophosgene generates the heterocumulene 89. Neither structural nor reactivity studies were undertaken with this complex. 

Cyclization of the isothiocyanates obtained from alicyclic )8-amino esters with thiophosgene and 2-chloroethyl or 3-chloropropylamine gave the thia-zolopyrimidinones 464-467 (96UP2). 

The reaction of pyrazolones (207) with 3-oxo-esters gives mainly the pyrazolo[l,2-a]pyrazol-l,5-(lff,5//) diones (208). However, with 207 (R = Ph), only oxazines 209 are obtained. Thermal and photochemical isomerization of 204 gives 209 (84CPB930, 84JAP59128384). Phenace-tylpyrazole (210) is cyclized to 211 with thiophosgene (84JOC3672). 

The 2-thione derivative of [l,3]dithiolo[4,5-f][l,2,5]thiadiazole 41 was prepared from the parent dichloride 163 following treatment of the intermediate disodium salt 171 with thiophosgene (Scheme 33) <1993SM(68)1914, 1997USP5703102>, while the bisthioester 103 was the precursor to the 2-one derivative 43 (Schemes 7 and 33) <1997SM(86)1871>. 

Condensation of ethyl anthranHates with isothiocyanates provides entry to a closely related compound in which the carbonyl at the 2 position is replaced by a thione. The sequence starts with the alkylation of pyrrolidine nitrogen in (92-1) with 2-bromoethylamine. Reaction of the primary amine in the product (92-2) with thiophosgene leads to the isothiocyanate derivative (92-3). Reaction of that reactive intermediate with methyl anthranilate (92-4) leads initially to the transient... 

Preparation of polycyclic orthocarbonate by reaction of 2,2-dihydroxy-biphenyl with thiophosgene [187]. 

Cyclic thionocarbonates (41) can be cleaved to olefins (the Corey-Winter reaction)274 by heating with trimethyl phosphite275 or other trivalent phosphorus compounds276 or by treatment with bis(l,5-cyclooctadiene)nickeI.277 The thionocarbonates can be prepared by treatment of 1,2-diols with thiophosgene and 4-dimethyIaminopyridine (DMAP) 278... 

They are believed to exert their effects by reaction of cellular thiols either with the intact compounds or with thiophosgene evolved by breakdown. This non-specific mode of action may be the reason why resistance to the sulfenyl compounds has not developed. 

Freund and Wolf10 reported that 2,4-diphenyl-l,2,4-thiadiazolidine-3,5-dithione was formed by heating l,3-diphenyl-2-thiourea with thiophosgene in benzene whereas, a 1,3-thiazetidine was produced at lower temperatures in ether (see Section II). Ohande181 has reported that 3,5-diamino-l,2,4-thiadiazoles are formed by the reaction of thiopseudoureas with carbon disulfide in the presence of bromine. Use has also been made of thioureas in the synthesis of 1,3,4-thiadiazolines (79) via reaction with the halohydrazones 78.185,186 The analogous reaction with solenoureas was recently reported by Bulka and Ehlers187 to yield 1,3,4-selenadiazolines. 

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