From Isocyanates and Isothiocyanates

The reaction of the substituted iminophosphorane 7 with isocyanates or isothiocyanates produces the carbodiimides 8.  

When two equivalents of the iminophosphorane are used with phenyl isocyanate, a 97 % yield of Me3SiCH2N=C=NCH2SiMe3, bp 77-80 °C/23 Torr is obtained. The same carbodiimide is obtained from the iminophosphorane and Me3SiCH2NCO.  

The reaction of tin-bis(trimethylsilyl)amido derivatives with isocyanates at —78 °C gives the carbodiimides, RN=C=NSiMe3, in 75-98 % yield. The tin-bis(trimethylsilyl)amido derivatives can be prepared in situ from MesSiNHR and n-BuLi, followed by SnCla. 

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Simple addition, in which both fragments of the NH molecule enter the new compound as in the preparation of alkanolamines from alkylene oxides, aminonitriles from unsaturated nitriles, and ureas and thioureas from isocyanates and isothiocyanates. 

N-Carbamyl- and N-thiocarbamyl-amidines from isocyanates and isothiocyanates respectively... 

The silylene 79 abstracts oxygen or sulfur from isocyanates and isothiocyanates. Cyclic sUoxanes are the products with isocyanates (equation 129) these probably arise by polymerization of the silanone, Ar2Si=0 (83). 

Isocyanates and isothiocyanates are reduced to methylamines on treatment with LiAlH4. Lithium aluminium hydride does not usually reduce azo compounds (indeed these are the products from LiAlH4 reduction of nitro compounds, 19-59), but these can be reduced to hydrazo compounds by catalytic hydrogenation or with... 

Imidazopyrimidopyrimidines such as 324 can be prepared simply by treatment of the pyrimidines 323 with isocyanates and isothiocyanates derived from a-amino esters (Equation 112) <1998HCA646>. 

Little is known of the biological and chemical behavior of the fluorodichloromethyl derivatives. Rio-tolysis of dichlofluanid results in the formation of N,N-dimethyl-N -phenylsulphamide, phenyl isocyanate and isothiocyanates and dimethylamidosulfonyl chloride GC-MS analysis also indicates the presence of bis-(fluorodichloromethyl) disulfide and two ketones, the latter being artifacts arising from the solvent, acetone. Dichlofluanid metabolism in plants yields N,N-dimethyl-N -phenylsulphamide (1 6), but nothing is... 

A general procedure for the synthesis of 5-chloro-l,2,4-thiadiazoles (289) is the reaction of amidines with trichloromethylsulfenyl chloride (329) in the presence of an acid acceptor (Scheme 152) (also see Scheme 102). 3-Halo derivatives (387 X = Cl, Br, I Scheme 153) have been obtained in moderate yields from the corresponding amines (386) using the Sandmeyer-Gatterman reaction (Scheme 153) (60JCS3234) (see Section 4.25.3.3.4). 3-ChIoro-l,2,4-thiadiazolin-2-ones of types (298) and (299) can be prepared by treatment of chlorosulfenylcarbonyl chloride (291) with carbodiimides and cyanamides, respectively (Scheme 154) (70AG(E)54). The isomeric products (270) and (274) are produced by the chlorination of mixtures of isocyanates and isothiocyanates (Scheme 155) (see also Scheme 95). 

In contrast to the acylation with carboxylic acid chlorides, secondary 1,1-enediamines react with isocyanates and isothiocyanates to give cleanly the /7-carbon acylated products. Carbamoyl-substituted enediamines (175) have been obtained from 174 and arylsulfonyl isocyanates (equation 67)140,141. 

The syntheses from [2+3] atom fragments are neither as general nor as important as those from [1+4] atom fragments. Wrackmeyer et at. have found thatm-2-boryl-l-stannylalkene 195 reacts with carbodiimides, isocyanates, and isothiocyanates as shown in Scheme 24 <2001CHE1396>. The reaction of 9-cyclopentyl-9-borabarbarlane 196 with acetone takes place with rearrangement to cyclooctatriene derivative 197 (Equation 33) <1998JOC3599>. 

It appears, then, that isocyanate and isothiocyanate CDAs are useful in LC resolutions of amines. Several of these agents are commercially available, and many others can be readOy prepared from a variety of commercially available optically active primary amines. The stereochemical stability of these CDAs is excellent, their reaction with amines is rapid and convenient, and the derivatives are readily and sensitively detected. These reagents are likely, therefore, to enjoy continued popularity. 

Amide acetals react with isocyanates and isothiocyanates to form. -acetals of parabanic acid (502) or dithioparabanic acid (503 Scheme 92). 2 -29.3S jypg gf compounds can be prepared from... 

The glycosyl ureide and thioureide obtained through the isocyanate and isothiocyanate routes were prepared from tetra-O-acetyl-a-D-glucopyranosyl bromide. The glycosyl ureides derived from this source are identical with those prepared by the acid-catalyzed condensation of D-glu-cose with urea and with thiourea. 

Aryl isocyanates and isothiocyanates with IA give the quinazolinones 206.261 263 Carbodiimides (207) yield either the aminoquinazolinones 208 (from I A)212 or the imino derivatives 209 (from N-substituted I A)211 (Scheme 35). 

N3-Substituted hydantoins and 2-thiohydantoins (9) are prepared by acid-catalyzed cyclization of the substituted ureido or thioureido acids (8) obtained from a reaction of a-amino acids with alkyl or aryl isocyanates and isothiocyanates.1 3,12 This method has been applied to prepare 2-selenohy-dantoins,13 and also in the stereospecific synthesis of (S)-(+)-l,5-cyclotrimethylene-3-phenyl-2-thiohydantoin.14... 

Nucleophilic carbenoids (also called ylides by some authors) react with heterocumulenes, such as isocyanates and isothiocyanates, to yield hy-dantoins, 2-thiohydantoins, and 2,4-dithiohydantoins via dipolar intermediates. Thus dimethoxycarbene adds to aryl isocyanates and isothiocyanates to form 5,5-dimethoxyhydantoins and dithiohydantoins.107 Thiazolium ylides (61) (resulting from thiazolium salts and NEt3 in DMF) give dipolar 1 1 adducts (62) or l 2-cycloadducts (63) with isocyanates or isothiocyanates.108-110 Other substrates are imidazolidine111 or 2-imidazoline derivatives.112... 

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