Thiourethanes

Hydroxythiazoles give 2-chIorothiazole derivatives almost quantitatively upon treatment with phosphorus oxychloride (221, 229, 428). This constitutes a convenient synthesis method for these compounds when the conversion of 2-aminothiazoles to 2-chlorothiazole derivatives fails. Esters of thiocarbamic acid or thiourethanes also react with a-halocarbonyl compounds to give the corresponding 2-alkoxythiazoles (50, 68, 209, 272). 

Woodward and co-workers utilized [Gu(MeCN)4]BF4 and (A)-BINOL-derived thiourethane ligand 87 in the addition reaction of trimethylaluminum to acyclic enones. Both yields and enantioselectivities were moderate (Scheme 44).130... 

Acid hydrolysis of thiazetidine 1,1-dioxide causes ring opening to the salt 262. Hydrolysis of 244 produces the ring-opened structure 263. Treatment of 264 with ethanol leads to thiourethane and substituted ureas. ... 

The same regiochemistry is observed when nitroimidazole (48-2, 48-3) acts as a nucleophile in unionized form. Thus, the reaction of a compound with benzoyl-aziridine (49-1) in the presence of boron trifluoride probably involves an initial salt formation with an amide attack by the imidazole results in a ring opening and the formation of the alkylated product (49-2) the free primary amine (49-3) is obtained on basic hydrolysis. Acylation of the primary amine with methyl thiochloroformate gives the corresponding thiourethane, carnidazole (49-4) [52]. 

TABLE 2. Physical Properties of Poly(thiocarbonate-co-thiourethane) Step 2 Derivatives Prepared by Condensing 2,4-Tolylene Diisocyanate with Step 1 Polythiocarbonates Described in Table 1 Prepared According to the Current Invention... 

Using poly(thiourethane) (PTU) as a polymer matrix for DHIs is a method for generating transparent polymers that may be used for different purposes, such as in ophthalmic lenses or information recording material. The compounds shown in the scheme (Scheme 23) were studied in such a PTU matrix. Typical fading or bleaching... 

Photochromic materials for information storage can be envisaged on the basis of the system shown in Figure 6.12. The dicyano DHI is a molecule that can be photochemically switched from the colorless form 7 to the colored form 9 and vice versa. So information could be stored with light of A.max = 400 nm and erased by light of A,max = 580 nm. Thus a dicyano-DHI/poly(thiourethane) matrix can be used to record information. In an initial study, the information was shown to last at least a week (Figure 6.12).58 59... 

Allyl chloride was treated with ammonium thiocyanate in refluxing n-butanol to give thiourethan 63, which when reacted with a-chloroacetyl chloride and benzaldehyde gave the 5-arylidene dione 64 [Eq. (19)].87... 

The isocyanate, SF5NCO, is easily hydrolyzed to SF5NH2 and C02, whereas SF5NCS is hydrolytically very stable. Both compounds undergo addition reactions with substrates containing easily replaceable hydrogen atoms, i.e., alcohols, thiols, and amines. With alcohols (thiols) the isocyanate and isothiocyanate give urethanes and thiourethanes, respectively. 

Polystyrene was prepared by Benicewicz [3] by bulk polymerization with 2,2 -azobisisobutyronitrile and had a polydispersity of 1.07 using either the low odor thioester, (IV), or thiourethane, (V), as chain transfer agents. 

Other methods of minor importance include the displacement of a thio or alkylthio group with ammonia giving aminopyridazines in poor yield, cleavage of a thiourethane with acid, hydrogenolysis of isoxazolo[3,4-d]pyridazin-7-ones or 4,7-diones, - or ring opening with acid of an imidazolo[4,5-d]pyridazine to yield 4,5-diamino - 3,6-dimethoxypy ridazine. ... 

In contrast to thioacyl chlorides, thiophosgene, CSCh, is readily accessible and conveniently handled making it an important reagent in the synthesis of thiocarbamoyl chlorides (15 ClCSNRa), 0-alkyl thiourethanes (ROCSNR 2), and thioureas (R2NCSNR2) (c/. Volume 6, Chapter 2.8). ... 

In accord with the special reactivity of a dithiocarboxylate moiety, 0,5-dialkyl dithiocarbonates, ROCSSR, yield 0-alkyl thiourethanes, ROCSNR 2, on addition of amines. Similarly, trithiocarbo-nates, (RS)2CS, yield thioureas. - ... 

The aromatic mustard oils are in part colourless liquids, in part crys tallisable solids, the lower members are easily volatile with steam, and possess a characteristic odour. In chemical behaviour they are very active. If they are warmed for a long time with an alcohol, they combine with the alcohol, addition taking place and a thiourethane is... 

See Tables of Compounds in Ellis and Honeyman for data on glycosyl isocyanates and isothiocyanates, and glycosyl-urethans, -thiourethans, -hydantoins, -thiohydantoins, and related compounds. 

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