Isothiocyanates 4-amino

Chen, S., HPLC enantiomeric resolution of phenyl isothiocyanated amino... 

Acetoxy isothiocyanates. Amino alcohols are converted to isothiocyanatoalkyl acetates on treatment with EtjN, CSj, and then AC2O-DABCO at room temperature. 

Condensation of 2-phenyl-4-amino-5-benzoylthiazole with cyanamide yields the pyrimidothiazole (Scheme 88) (133) (49) 2-imino-3-aryl-4-amino-5-carbethoxy-4-thiazolines condense similarly with alkyl isothiocyanates (276). 

Treatment of 2-imino-3-phenyl-4-amino-(5-amido)-4-thiazoline with isocyanates or isothiocyanates yields the expected product (139) resulting from attack of the exocyclic nitrogen on the electrophilic center (276). Since 139 may be acetylated to thiazolo[4,5-d]pyrimidine-7-ones or 7-thiones (140). this reaction provides a route to condensed he erocycles (Scheme 92). 

The problem is more complicated when the ambident nucleophile. 2-aminothiazole, reacts with an ambident electrophilic center. Such an example is provided by the reaction between 2-amino-5-R-thiazole and ethoxycarbonyl isothiocyanate (144), which has been thoroughly studied by Nagano et al. (64, 78, 264) the various possibilities are summarized in Scheme 95. At 5°C, in ethyl acetate, the only observed products were 145a, 148. and 150. Product 148 must be heated to 180°C for 5 hr to give in low yield (25%) the thiazolo[3.2-a]-s-tnazine-2-thio-4-one (148a) (102). This establishes that attack 1-B is probably not possible at -5°C. When R = H the percentages of 145a. 148. and 150 are 29, 50, and 7%, respectively. These results show that ... 

The HSAB pattern may also be reversed by steric effects a Japanese patent describes the preparation of 3-(4-R-thiazolyl-2)thioallophanic acid esters (151) by reaction between 2-amino-4-R-thiazoles (4-R = H or low alkyl) and isothiocyanate formic acid ester (Scheme 96) (309). 

The ambident reactivity of 2-amino-4,5-disubstituted thiazoles toward benzoylthiocyanate 153 has been studied (311) and parallels that of ethoxycarbonyl isothiocyanate (Scheme 98) the percentages of 154. 155. 

TABLE n-36. 2,5-DIAMINOTHIAZOLE DERfVATIVES FROM a-AMINO-NITRILES AND ISOTHIOCYANaTES. 

Isothiocyanates (R,NCS) react with l,4-diamino-2-butynes to give 2-amino-5-p-aminoethylidene-A-2-thiazolines, which can be isomerized into 2-amino-5-p-aminoethylthiazoles with Rj, R2, Rs = alkyl (Scheme 130) (789). 

Edman degradation (Section 27 13) Method for determining the N terminal amino acid of a peptide or protein It in volves treating the material with phenyl isothiocyanate (CgH5N=C=S) cleaving with acid and then identifying the phenylthiohydantoin (PTH derivative) produced Elastomer (Section 10 11) A synthetic polymer that possesses elasticity... 

Substitution of alkaline cyanates by isocyanates allows the preparation of 3-substituted hydantoias, both from amino acids (64) and amino nitriles (65). The related reaction between a-amino acids and phenyl isothiocyanate to yield 5-substituted 3-phenyl-2-thiohydantoiQS has been used for the analytical characterization of amino acids, and is the basis of the Edman method for the sequential degradation of peptides with concomitant identification of the /V-terminal amino acid. 

The most used EIA reagents conjugate a fluotophote such as fluorescein-isothiocyanate (EITC) or thodarnine—isothiocyanate to antibody (or antigen) free amino groups. Examples of other commonly used fluotophotes for EIA and their spectral characteristics ate presented in Table 3. EIA assays ate available in sandwich and competitive formats similar to EIAs. Unlike EIA kits which can be used directly with visual color deterrnination, EIAs require a fluorometer, and thus ate primarily laboratory-based. 

Sulfoxides occur widely in small concentrations in plant and animal tissues, eg, aHyl vinyl sulfoxide [81898-53-5] in garlic oil and 2,2 -sulfinylbisethanol [3085-45-8] as fatty esters in the adrenal cortex (1,2). Homologous methyl sulfinyl alkyl isothiocyanates, which are represented by the formula CH3SO(CH2) NCS, where n = 3 [37791-20-1], 4 [4478-93-7], 5 [646-23-1], 8 [75272-81-0], 9 [39036-83-4], or 10 [39036-84-5], have been isolated from a number of mustard oils in which they occur as glucosides (3). Two methylsulfinyl amino acids have also been reported methionine sulfoxide [454-41-1] from cockroaches and the sulfoxide of i -methylcysteine, 3-(methylsulfinyl)alaiiine [4740-94-7]. The latter is the dominant sulfur-containing amino acid in turnips and may account in part for their characteristic odor (4). 

Azaindolizine, 5-chloro-nucleophilic substitution, 4, 458 8-Azaindolizine, 7-chloro-nucleophilic substitution, 4, 458 Azaindolizines basicity, 4, 454 electronic spectra, 4, 445 electrophilic substitution, 4, 453 halogenation, 4, 457 hydrogen/deuterium exchange, 4, 458 NMR, 4, 447, 449 nucleophilic attack, 4, 458 protonation, 4, 453 reaction with isothiocyanates, 4, 513 reactions, 5, 267 reviews, 4, 444 UV spectra, 4, 446, 449 Azaindolizines, amino-tautomerism, 4, 452... 

This thiourea, prepared from an amino acid and phenyl isothiocyanate, is cleaved by anhydrous trifluoroacetic acid (an N-COCF3 group is stable), and by oxidation (/72-CIC6H4CO3H, 0°, 1.5 h, 73% yield H2O2/ACOH, 80°, 80 min, 44% yield). ... 

The synthesis of 5-aminothiazoles via the reaction of isocyanate derivatives with aminomalononitrile p-toluenesulfonate (AMNT) has been investigated. It was found that AMNT 12 reacted with alkyl and aryl isothiocyanates in l-methyl-2-pyrrolidine (NMP) to furnish 5-amino-2-(alkylamino)-4-cyanothiazoles (13a) and 5-amino-2-(arylamino)-4-cyanothiazoles (13b-c) in 44-81 % yields. " ... 

Undoubtedly these reactions proceed via an intermediate ureido or thioureido derivative. These compounds have been obtained by Dornow and Hahmann by the action of potassium cyanate or ammonium isothiocyanate on 2-amino-4,6-dimethylnicotinic acid (11), but whereas the urea (12, X = 0) was converted into the pyrido[2,3-li]-pyrimidine-2,4(lI/,3/7)-dione (13, X = 0) by the action of heat, the thiourea (12, X = S) was unchanged after similar treatment. 

Amino esters (26) have also been shown to yield pyrido[2,3- Z]-pyrimidin-4(3I/)-ones (25, 27) when treated with isocyanates and isothiocyanates. The reactions proceed via intermediate ureido and thioureido derivatives. 

As shown by Oliveri-Mandalli,and by Lieber et al., 5-sub-stituted-amino-l,2,3,4-thiatriazoles are also formed by reaction of isothiocyanates with hydrazoic acid. When sodium azide is used instead of the free acid the isomeric mercaptotetrazoles are formed. 

Treatment of 3-amino-4-oxoquinazolines (9) with cyanamide gave the 2-amino-l,2,4-triazolo [l,5-c]quinazolines 11 as a result of cyclodehydration of the intermediate 3-guanidino-4-oxoquinazolines 10 (68CB2106) (Scheme 9). Similarly, reaction of the 3-amino-4-thioxoquinazoline 12 with alkyl or aryl isothiocyanates yielded the mesoionic l,2,4-triazolo[l,5-cjquinazolines 14 (84S881) (Scheme 10). 

Diaminopyrimidines (22) were also cyclized with cyanogen bromide (90JHC851) or phenyl isothiocyanate (97PHA753) to give the corresponding 2-amino- or 2-anilino-l,2,4-triazolo[l,5-c]pyrimidines 30 and 31 respectively (Scheme 15). 

Cycloaddition of 2-nitrosopyridine 48 with nitrile oxides can give either di-A -oxides such as 49 or 3-mono-A -oxides such as 50 (93JHC287). In general, greater electron withdrawing character in the aromatic substituent appears to favor formation of the di-A -oxides. Sulfur ylides such as compound 51 are obtained from aryl isothiocyanates and l-amino-2-methylthiopyridinium iodides (84JCS(P1)1891) nitrogen ylides can be obtained from a similar reaction (86H(24)3363). 

The amino group of 3,4-dihydro-2//-pyrimido[2,l-n]isoquinoline 421 (R = H) was acylated with different isocyanates and phenyl isothiocyanate (98JMC1050). 

Piperazine NH group of 9-fluoro-10-(l-piperazinyl)-7-oxo-2,3-dihydro-7//-pyrido[l,2,3-<7e]-l,4-benzothiazine-6-carboxylate was reacted with 4-nitrophenylsulfonyl chloride, 2,6-dichloropyrazine, 2,6-dichloropyridine in DMF in the presence of pyridine, and with 4-nitrophenyl isothiocyanate in aqueous acetone in the presence of KOH (01MIP13). A side chain amino group on a 2,3-dihydro-7//-pyrido[l,2,3- fe]-l,4-benzothiazin-7-one skeleton was acylated (OOMIPIO). 

Chloro-2-amino-0 -methyl-Ophenylbenzyl alcohol Ethyl mustard oil (ethyl isothiocyanate)... 

Free amino acids can be derivatized with isothiocyanates to phenyl- or methyl-thiohydantoin derivatives. The thiohydantoins can be separated on a CSP with poly-[Af-acryloyl-L-phenylalanine ethylester] (Chiraspher ) as a chiral selector [25]. This CSP offers a known selectivity for many five-membered heterocyclic rings. 

Nucleophilic addition of the peptide terminai amino group to p nenyi isothiocyanate (PITC) gives an /V-phenylthiourea derivative. 

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