Thiocyanato

A-4-Thiazoline-2-ones and ring substituted derivatives are usually prepared by the general ring-closure methods described in Chapter II. Some special methods where the thiazole ring is already formed have been used, however. An original synthesis of 4- 2-carboxyphenyl)-A-4-thiazoline-2-one (18) starting from 2-thiocyanato-2-halophenyl-l-3-indandione (19) has been proposed (Scheme 8) (20, 21). Reaction of bicyclic quaternary salts (20) may provide 3-substituted A-4-thiazoline-2-one derivatives (21) (Scheme 9) (22). Sykes et al. (23) report the formation of A-4-thiazoline-2-ones (24) by treatment ef 2-bromo (22) or 2-dimethylaminothiazole (23) quaternary salts with base (Scheme 10). 

Thus reduction of the 5-thiocyanato group of 151 by zinc (333, 360, 361) or aqueous sodium sulfide (348. 362), hydrolysis of the thiouronium group (7, 363, 364), and deacetylation of the 5-acetylthiothiazole with cold piperidine (365) have been performed to yield the 5-mercapto-thiazole (Scheme 78). It must be pointed out that depending on the experimental conditions, bis(5-thiazolyl(sulfide may be observed as a byproduct (363, 365). Thus 5-amino-4-methylthiazole (152) treated with... 

Nucleophilic substitution of the 5-halo substituent on a thiazole ring by a thiocyanato group (348, 362, 370-376) or a thiouronium group (364, 377) affords the thiocyanato and thiouronium precursors."... 

Nitric acid oxidizes the 5-thiocyanato group to the sulfate (360). 

CHLOROTHlAZOLE DERIVATIVES FROM a-THIOCYANATO-KETONES AND DRY HYDROCHLORIC ACID IN ETHEREAL SOLUTION... 

Thiocyanato-2-aminothiophenes give by ring closure the corresponding 2-aminothieno[2,3d]thiazoles (764). 

In a similar way the use of the 2-methyl-3-isothiocyanato-4-thiocyanato-hept-3-ene (252) prepared from thiocyanogen and the oxoal-kylene phosphorane (251) yields the 2-anilino-4-propyl-5-isopropyl-thiazole (253) by condensation with aniline (Scheme 128). 

Fig. 3. Representive stmctures for compounds of molybdenum(V) (a) dimolybdenum dodecachloride [26814-39-17, M02CI2Q, the dimer of molybdenum pentachloride (b)pentakis(thiocyanato)oxomolybdenum(V), MoO(NCS)g (c) Mo20 (NCS)g (d) Mo2(S2)g (e) Mo2Sg (f) Mo2S (S2CNR2)2 (g)...

Salts containing pentavalent tungsten may be obtained by the reduction of alkaU tungstate in concentrated hydrochloric acid. Salts of types M(I)2(W0C1 ) (green), M(I)(WOCl (brown-yeUow), and M(I)(WOCl 2 ) h ve been isolated. Thiocyanato and bromo salts are also known. 

A thiocyanato group can be introduced by treatment of the corresponding chloro or bromo compounds with ammonium, sodium or potassium thiocyanate. In polychloro compounds only one halogen is replaced. 

There are several minor routes to pyrimidinethiones from thiocyanato- or amino-pyrimidines or by direct introduction of sulfur, but they are preparatively unimportant. 

Benzothiazole, 2-amino-6-thiocyanato-azo dyes from, 1, 328 Benzothiazole, 2-aryl-synthesis, 6, 321 Benzothiazole, 2-arylamino-synthesis, 6, 323 Benzothiazole, 2-aryloxy-Fries rearrangement, 6, 289 Benzothiazole, 2-benzyl-picrate, 6, 252 Benzothiazole, 2-chloro-dyes from, 1, 321-322 synthesis, 6, 323 Benzothiazole, 2,3-dihydro-oxidation, 6, 272 Benzothiazole, 2-dimethylamino-synthesis, 5, 128... 

Purine, 9- -D-ribofuranosyl-6-selenoxo- 1,6-dihydro-synthesis, 5, 597 Purine, 6-thiocyanato-acylation, 5, 559 Purine, 2-thioxo-synthesis, 5, 589 Purine, 8-thioxo-iodination, 5, 559 synthesis, 5, 577, 597 Purine, 2-thioxo-2,3-dihydro-synthesis, 5, 572 Purine, 6-thioxo-1,6-dihydro-acylation, 5, 559 dethiation, 5, 558 halogenation, 5, 559 hydrolysis, 5, 560 methylation, 5, 535 oxidation, 5, 560 synthesis, 5, 572, 596 Purine, 8-thioxo-7,8-dihydro-acylation, 5, 559 Purine, 2,6,8-trichloro-alkylation, 5, 530 amination, 5, 562 reactions, 5, 561, 562 with hydriodic acid, 5, 563 with pyridine, 5, 562 synthesis, 5, 598 Purine, 2,6,8-trichloro-7-methyl-synthesis, 5, 557 Purine, 8-trifluoromethyl-synthesis, 5, 574... 

The complex coordination chemistry of Pb" is also beginning to be actively explored and some unusual stereochemistries are emerging. Thus, the mononuclear ( ) -nitrato)bis(phenanthrolene)(A-thiocyanato) complex [Pb(phen)2(NCS)( ) -NO3)] has 7-coordinate Pb" with a large vacancy... 

It should be noted that, by convention, the ambidentate ligand is always written with its donor atom first, i.e. NO2 for the nitro, ONO for the nitrito, NCS for the A-thiocyanato and SCN for the 5 -thiocyanato complex. Differences in infrared spectra arising from the differences in bonding are often used to distinguish between such isomers. 

Thiocyanato groups in pyrimidines (138 where R2 is chloro or amino) have been replaced with amines, ethoxide ion, phenoxide ion, and thiourea. 

Thiocyanato-30 -methanesulfonyloxy-50 -androstan-17(3-01-17-acetate Potassium hydroxide... 

The participation of a monomer molecule in the initiation step of polymerization has not been required in the examples described so far. Tris(thiocyanato) tris(pyri-dine) iron(III) complex forms a complex with methyl methacrylate [46]. By subjecting the compound to UV radiation, the complex decomposes to give SCN as the initiating radical. 

Product 15 was eventually transformed into methyl 4,6-dideoxy-a-D-xylo-hexopyranoside by reductive desulfurization. A related reaction is the formation (41) of the 4-thiocyanato derivative 17 in 47% yield from 16 (140°C., 22 hours in N,N-dimethylformamide). This has been suggested as a good route to 4-deoxy-D-xt/Zo-hexoses compared with the available methods (43). 

The reactivity at the C-4 position of hexose and hexoside sulfonates has been demonstrated in the gluco and galacto series and could undoubtedly be extended to other sugars as well. In another example (25), methyl 2,3-di-0-benzoyl-4-0-p-tolysulfonyl-a-D-glucopyranoside (18a) was treated with potassium thiocyanate in N,N-dimethylformamide at 140°C. for 9 hours to give the C-4 epimeric thiocyanato derivative 19 in 34% yield. The corresponding 4-p-bromobenzenesulfonate (18b) however, afforded a 55% yield of 19 in only 2% hours of reaction time. 

Aminodebromination of 4-bromo-l//-3-benzazepin-2-amine (25) with triethylamine occurs readily and results in formation of the quaternary salt 26 (see also Section 3.2.1.5.6.), whereas attempts to effect nucleophilic substitution of bromide with primary or secondary amines gives only tarry mixtures.41 The bromo group is also resistant to displacement by azide and benz-cncthiolate but undergoes substitution with thiocyanate ion in hot dimethylformamide to give the 4-thiocyanato derivative 27 rather than the thiourea by addition at the amine function. 

Borane, 1-methylbenzylaminocyanohydropyrrolyl-, 3, 84 Borane, thiocyanato-halogenohydro-, 3,88 Borane, trialkoxy-amine complexes, 3, 88 Borane, triaryl-guanidine complexes, 2,283 Borane, trifluoro-complexes Lewis acids, 3,87 van der Waals complexes, 3, 84 Borane complexes aminecarboxy-, 3,84 aminehalogeno-, 3, 84 amines, 3, 82, 101 B-N bond polarity, 3, 82 preparation, 3, 83 reactions, 3, 83 bonds B-N, 3, 88 B-O, 3, 88 B-S, 3, 88 Jt bonds, 3, 82 carbon monoxide, 3, 84 chiral boron, 3, 84 dimethyl sulfide, 3, 84 enthalpy of dissociation, 3, 82... 

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