Benzyl isocyanates

Benzyl chloride reacts with alkaH hydrogen sulfides, sulfides, and polysulfides to yield benzenethiol, dibenzyl sulfide, and dibenzyl polysulfide, respectively. With sodium cyanate it forms benzyl isocyanate (20). 

Multicomponent reaction of 2-aminomethylpiperidine benzyl isocyanate and 4-chlorobenzaldehyde in the presence of InCl3 as catalyst provided 4-benzylimino-3-(4-chlorophenyl)pyrido[l,2-+]pyrazinium chloride <2005OL2329>. First, a 3,4-dihydro-477 derivative was formed, which was oxidized under the reaction conditions. Reaction of... 

The reaction of pentafluorophenyl isocyanate with thiadiazole 8 in acetonitrile at room temperature gave 5-penta-fluorophenylureido-l,3,4-thiadiazole-2-sulfonamide 105 (Equation 31) <2004JME2796>. Similarly, 2-amino-l,3,4-thia-diazole 37 reacts with benzyl isocyanate in dry THF to afford the l,3,4-thiadiazol-2-yl urea 106 in 94% yield (Equation 32) <1999JME1525>. 

In the reaction of the conformationally restricted epoxy alcohol 84 and methyl or benzyl isocyanate, the epoxy carbamate 85 was formed. Cycliza-tion of 85 in tetrahydrofuran in the presence of sodium hydride gave the oxazinone 86 in approximately 20% yield, and the oxazolidinone 87 (R = Me, CH2Ph) in 40-60% yield. The formation of the two products can be rationalized by different nucleophilic attacks on the urethane nitrogen. With increasing nucleophilicity of the nitrogen, the regioselectivity of the reaction is shifted toward the formation of 87 (92TL3009). 

Takatsuki and co-workers have recently introduced the 3, 5 -0-sulfinyl group which has the dual purpose of protection and activation in nucleoside chemistry. For example, compound 13, prepared by protection of 12 as shown in Scheme 3, underwent reaction with benzyl isocyanate followed by intramolecular displacement of the sulfmate to give the product 14 <2004TL137>. A similar approach has also been used to prepare thioglycoside epoxides <2004CAR2895>. 

Triaryl phosphites are not effective as catalysts and alkyl isocyanates usually are not cyclized by phosphites at all, although benzyl isocyanates are reported to yield the corresponding uretidinediones with 1,2-dimethylimidazole as a catalyst (75S463). 

The synthesis of the pyrimidine ring represents a well-studied group of heterocyclization reactions based on enamines. One of the important approaches involves the reaction of enamines with assorted isocyanates and isothiocyanates. Thus, a reaction of enaminonitriles with benzyl isocyanate or phenyl isocyanate gives C- and N-adducts (190a and 190b, respectively) or their mixtures, which are transformed in a single step into 4-pyrimidinone (191) and 2-pyrimidinone (192) derivatives (94JHC329). The... 

Amino alcohols Azidotrimethylsilane, 24 Benzyl isocyanate, 30 Diethylamine, 312 Morpholine, 14 Pyrrolidine, 14... 

Containing one nitrogen, one oxygen—other compounds Benzyl isocyanate, 30 N-Methyl-N,0-bis(trimethylsilyl)-hydroxylamine, 187 Norephedrine, 200 Potassium f-butoxide, 252 Vinyltrimethylsilane, 343 Containing one nitrogen, one sulfur N-Methyl-o-aminothiophenol, 184 Containing two nitrogens Pivaldehyde, 249... 

SYNS BENZENE, l-(l-ISOCYANATO-l-METHYLETH-YL)-3-(l-METHYLETHENYL)- a-a-DIMETHYL-m-ISOPROPENYL BENZYL ISOCYANATE ISOCYANIC ACID, m-ISOPROPENYL-a-a-DIMETHYL BENZYL ESTER m-TMI... 

DIMETHYL-a-IONONE see COW780 a-a-DIMETHYL-m-ISOPROPENYL BENZYL ISOCYANATE see IKG800 DIMETHYL-5-(l-ISOPROPYL-3-METHYLPYR, ZOLYL)CARBAMATE see DSK200... 

Analysis of Reagent Purity the enantiomeric purity of the reagent can be determined by either NMR or HPLC analysis of derivatives produced from a-methoxy-a-(trifluoromethyl)benzyl isocyanate, a-methoxy-a-(trifluoromethyl)benzyl acid chloride, or 2 -methoxy-l,l -binaphthyl-2-carboxylic acid chloride. ... 

The Curtius rearrangement of the acyl azide derived from optically pure a-methoxy-a-(trifluoro-methyl)phenylacetic acid (MTPA 48) also proceeds with retention of configuration, giving a-methoxy-a-(trifluoromethyl)benzyl isocyanate (49 equation 26). The isocyanate (49) is useful for the determination of the enantiomeric composition of optically active primary and secondary amines. 

CIC Linalool is responsible for the basic fruity, floral topnote. Methyl-(methylthio)-acetate and butyric acid impart the butyric, rotten character and benzyl isocyanate is the key component for the radish smell of the seeds. 

Nonaromatic Isocyanates. These structures in which the isocyanato functions are not attached directly to an aromatic ring (Figure 3.38). Most often they are also referred to as aliphatic isocyanates, even though they may actually be benzylic isocyanates [85]. 

The problem of discoloration of PURs derived from benzylic isocyanates is not solved completely because of slow oxidation at the benzylic hydrogens. 

Scheme 9.3 Reaction of NBDPZ (10) with propyl isocyanate (11), benzyl isocyanate (12) and toluene-2,4-diisocyanate (13) to give the corresponding NBDPZ-urea derivatives (14).

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