Isothiocyanates, RNCS

Infrared, nuclear magnetic resonance, ultraviolet, optical rotary dispersion and circular dichroism measurements have been used for the spectral analysis of thiiranes. A few steroidal thiiranes have been reported to possess infrared absorption in the range from 580 to 700 cm The intermediate thiocyanate derivatives (RSCN) have a strong sharp peak at 2130-2160 cm the isomeric isothiocyanate (RNCS) shows a much stronger but broad band at 2040-2180 cm. ... 

The 1,2,3,4-thiatriazoles are unstable. They decompose on heating— in some cases even at room temperature—and in many cases they melt with detonation. Accordingly the Ng-group has not been stabilized much by ring closure. The compounds behave in this respect similarly to azides and this fact doubtlessly delayed the recognition of their true nature. On heating with a solvent the thermal decomposition of 5-aryl-1,2,3,4-thiatriazoles proceeds according to Eq. (4). By the photochemical decomposition small amounts of the isothiocyanate, RNCS, are formed in addition to the nitrile. ... 

Salts of dithiocarbamic acid can be prepared by the addition of primary or secondary amines to carbon disulfide. This reaction is similar to 16-9. Hydrogen sulfide can be eliminated from the product, directly or indirectly, to give isothiocyanates (RNCS). Isothiocyanates can be obtained directly by the reaction of primary amines and CS2 in pyridine in the presence of DCC. ° In the presence of diphenyl phosphite and pyridine, primary amines add to CO2 and to CS2 to give, respectively, symmetrically substituted ureas and thioureas ... 

Note that carbon monoxide inserts into the Zr-H bond of 1 (2 equiv.) to afford an T -formaldehydo-type complex [(Cp2ZrCl)]2(g-CH20) [200-202]. Iminoacyl zir-conocene complexes are formed after addition of 1 to isonitriles [203]. Carbon dioxide [183, 202] is reduced to formaldehyde with 1 (2 equiv.). C02-like molecules such as isocyanates RNCO [204], isothiocyanates RNCS [205], and carbodiimides RNCNR [204] are readily converted to the corresponding bidentate form-amido ligands. 

Various isothiocyanates (RNCS R = Buc, Ph) and CS react with exclusively with the Mg-C bonds of dinuclear Al-Mg compounds to give dinuclear insertion products (Scheme 7). In the case of the reaction of Me2Al(/i-Et2N)2Mg(CH3) 2 with PhNCO, a tetranuclear insertion product is formed.290... 

The anodic oxidation of alkyl isothiocyanates RNCS in wet acetonitrile (AN) involves the formation of two possible... 

Ammonium thiocyanate reacts with alkyl hahdes forming alkyl thiocyanates, RSCN, which may also rearrange to alkyl isothiocyanates, RNCS ... 

Isocyanides can be converted to isothiocyanates (RNC — RNCS) by treatment with a disulfide such as PhCOSSCOPh and thallium(I) acetate or lead(II) acetate.43"... 

R CO-5-R-ttaH) tetrazoles, respectively (114). The azide Pd(N3)2-(PPh3)2 also undergoes 1,3-cycloaddition reactions with organic isonitriles (RNC) (15) and isothiocyanates (RNCS) (114) to afford the complexes 42 and 43 (M = Pd), respectively. N-l-Coordinated tetrazolate chelate complexes 44 and 45 are formed by treatment of... 

The reaction of alkyl isothiocyanates, RNCS, with diphenylphosphinic hydrazide (338) in benzene has been reported.308 The bis(diethylamino)[(methylthio)thiocarbon-yl]carbenium salts (339 X = I or BF4) display ambident reactivity and can react either at carbenium carbon (hard nucleophiles) or at the thiocarbonyl sulfur atom (soft nucleophiles).309 Electrochemically generated superoxide reacts with dithioic S,S -diesters (dicarbothiolates) (340 Ar = C5H3N or C6H4) to give the monocarboxylate anions in 100% yield before giving the dicarboxylate anions.310... 

The reaction of ethyl / -aminocrotonate (158) with isothiocyanates RNCS (R = p-02NC6H4, / -02NC6H4C0, EtOCO or Et02CCH2) yields the thiocarbamates 159, which cyclize to isothiazoles on treatment with bromine (equation 70)9°. 

Glucosinolates (sulfosugars yielding specific isothiocyanates (RNCS) on hydrolysis) Goitrin (=(—)-5-Vinyloxazolidine-2-thione) (oxazolidine)... 

The titanocene vinylidene intermediate Cp2Ti(=C=CH2) formed by ethane or methane elimination from titanacyclobutane (4) or Cp2Ti(CH=CH2)Me, respectively, reacts with isothiocyanates, RNCS (R = CeHn, Ph or r-Bu), by a [2 + 2] cycloaddition, to give the titanathietane complexes (8). In all cases, the regioisomer in which the S atom is bonded to Ti is found as the primary product. Upon heating in the presence of pyridine, a rearrangement of (8) to the regioisomeric titanacyclobutane derivative (9) was observed (equation 12)." ... 

The anodic oxidation of alkyl isothiocyanates (RNCS) in MeCN is highly dependent on the nature of the alkyl group [227]. Primary RNCS afforded exclusively five-membered heterocyclic products LXXVI-LXXVIII, whereas secondary and tertiary RNCS involved formation of a-cleavage products (RNHCOCH3) or isocyanates (RNCO) due to substitution of sulfur for oxygen processes. 

The 2-imino-l,3-oxathiolanes (43) may be prepared by reaction of isothiocyanates, RNCS, with either (310) <77BCJ3271> or (311) <74JOM(72)103>, and reaction of the latter with CSj gives 1,3-oxathiolane-2-thione (42). 

Type H Syntheses of Thiazoles (S—C + C-N-C). Base-induced cycloadditions of tosylmethyl isocyanide (4-MeC6H4S02CH2NC) and an isothiocyanate RNCS (R = alkyl, allyl, PhCO, aryl, etc.) have been investigated. Depending on the reaction conditions, thiazoles (91) and/or imidazoles (92) are obtained. A high-yield ring-transformation of (91) to (92) occurs in THF/ BuLi. ... 

Type H Syntheses (S-C + C-N-C). Isothiocyanates (RNCS) and methyl isocyanoacetate react, in THF containing Bu0 , to form thiazoles (83 R=Me,Et,Bu,cyclohexyl,benzyl,Ph,4-ClCgH, R1=Me) in 53-77 yield. Some (83) were saponified to corresponding carboxylic... 

From P-Aminocrotonates Type C). A one-step synthesis of glycosylamino-isothiazoles (5) involves the reaction between a glycosyl isothiocyanate (RNCS) and MeC(NH2)=CHC02Et. ... 

Isothiazolo[3,4-J]pyridines.—The reaction of uracils with glycosyl isothiocyanates (RNCS) gives the 3-glycosylamino-5,7-dimethylisothiazolo[3,4-Similar compounds (39 R = SMe) are obtained from the reaction between uracils and carbon disulphide, dimethyl sulphate, and alkali. 

The reagent converts primary alcohols into thiocyanates, RSCN, in yields of about 60-957o. Tertiary alcohols are converted into isothiocyanates, RNCS, and secondary alcohols are converted into mixtures of thiocyanates and isothiocyanates. 

Cyclopentadienylbis(triphenylphosphine)cobalt catalyzes the oligomerization of acetylenes and cooligomerization of acetylenes and nitriles or acetylenes and isothiocyanates, RNCS " [scheme (9.165)]. 

---