2-cyano-l-hydroxy

Habib and co-workers observed the rearrangement of 2-quin-oxalinone 4-oxides (219) on treatment with acetic anhydride to 1,3-diacetyl- or l-acetyl-3-acyl-2-benzimidazolones (220).219 Recently, the ring contraction of 2-azidoquinoxaline 1-oxide to 2-cyano-l-hydroxy-benzimidazole has been reported.220... 

Mild acidic hydrolysis of amino nitrile 369 gave m-4,9a-/7-rra r-9-7/-9-benzyloxy-4-phenyl-3,4,9,9a-tetrahydro-17/,67/-pyrido[2,l-d[l,4]oxazin-l-one <1996TL4001>. (2A)-2-Cyano-l-[(lR)-2-hydroxy-l-phenylethyl]piperidin-6-one, on standing for 20 days in ethanol saturated with HC1 gas, afforded (4/ ,9aA)-4-phenylperhydropyrido[l,2-4[l,4]oxazine-l,6-dione, which was sometimes accompanied by the unstable (26 )-l-[(l/ )-2-hydroxy-l-phenylethyl]-... 

The 6//-l,3-thiazin-6-iminium hydroperchlorate salts 78-81 give interesting products when treated with nucleophiles <2003H(60)2273>. Hydrolysis of 6-imino-6//-l,3-thiazine hydroperchlorate 78 affords (2Z,4Z)-2-cyano-5-hydroxy-5-phenyM-azapenta-2,4-dienethioamide 82 in excellent yield, while treatment with morpholine gives 2-(morpholinomethylene)malononitrile 83 and thiobenzamide. The 5-(ethoxycarbonyl) -(methylthio)-2-aryl-6/7-l,3-thiazin-6-iminium salts 79 and 80 react with hydroxide or morpholine to afford ethyl 4-(methylthio)-2-aryl-6-thioxo-l,6-dihydropyrimidine-5-carboxylates 84 and 85. In the case of the 4-chloro analogue 80, the (Z)-ethyl 2-(5-(4-chlorophenyl)-37/-l,2,4-dithiazol-3-ylidene)-2-cyanoacetate 87 is also formed for the reaction with sodium hydroxide. The 1,2,4-dithiazoles 86 and 87 can be obtained as the sole product when 79 and 80 are treated with sodium acetate in DMSO. Benzoxazine 88 is isolated when the iminium salt 81 is treated with morpholine or triethylamine. Nitrile 89 is formed as a ( /Z)-mixture when 6-imino-67/-l,3-thiazine hydroperchlorate 79 is reacted with triethylamine and iodomethane in methanol <2003H(60)2273>. 

Attempted oxidation of 3-cyano-l-hydroxy-2-methylindole (111) by cold aqueous potassium permanganate or sodium dichromate in hot acetic acid caused deoxygenation to 3-cyano-2-methylindole, and photolysis of the 0-acetyl and 0-methoxycarbonyl derivatives gave the same product... 

Benzyl-1-isocyanate- 2J23 1 -Cyano-1 -(a-hydroxy-benzyl)- 1360 2-Cyano-l-methoxy-l-phenyl- 764, 2121, 2126. 2134 Cyclopropenone Dimethylamino-phcnyl- 2292... 

Carboxy-l-diisopropylaminocar-bonyl-1-methyl- 1358 2-Cyano-l-[(3,3-dimethyl-3-hydroxy-2-propy loxycarbonyl)-methy I]-1 -... 

Cyano-l, 2-dimethoxycarbonyl-ethenyI)- 2801 9-(l H-Cyclopropabenzen-1 -yliden)- 2965 9-(2,3-Dimethyl-2-cydopropenyl)- 2968 9-(Dimethyl-2-cyclopropenyliden)- 2967, 2968 9-( 1,1 -Dimethy 1-2-formyl-propy 1)- 2517 9-( 1,1 -Dimethy 1-3-oxo-butyl)- 2517 9-(2,3-Diphenyl-2-cyclopropenyl)- 2968 9-(Diphenyl-2-cyclopropenyliden)- 2968 9-(3,3-Diphenyl-propadienyliden)- 2415 9-Hydroxy-9-(3-oxo-3-phenyl-propyl)- 2002, 2517 9-(2-Methoxycarbonyl-1 -phenyl-ethyl)- 2804 9-(2-Oxo-1 -propyl-pentyliden)- 2808 9-(3-Oxo-l, 1,2,2-tetramethyl-butyl)- 2517 9-Propyl- 2055 1,4,9-Triphenyl- 2940... 

Surprisingly, 3-cyano-l-hydroxy-2-methylindole with potassium permanganate or sodium dichromate suffers only dehydroxylation, whereas with 35% nitric acid in benzene a 68% yield of iV-acetyl-2,l-benzisoxazolin-3-one (181 R1 = Ac, R2 = H) is obtained. Oxidation with 70% nitric add produces the nitro derivative 181 (R1 = Ac, R2 = N02) in high yield (70%).257 The N-acetylacyl cyanide 180 (R1 = CN, R2 = Ac) is the presumed intermediate. 

The kinetically equivalent mechEinism involving attack by a coordinated hydroxyl was rejected by these authors because (a) reaction of 2-cyano-l,10-phenanthroline with the Zn(II) or Cu(II) monocomplexes of pyridine-2-carboxal-doxime, 2-aminomethyl-8-hydroxyquinoline, or the Cu(II) monocomplex of 2-hydroxy-l,10-phenanthroline gives the amide as the sole product, (b) The product of the Cu(II)-catalyzed reaction is not altered by the presence of ethylene-diamine or hydroxyethylethylenediamine, although the rate of the reaction is inhibited, (c) The presence of high concentrations of either ethanol or ethanolamine... 

There is one more way for conversion of ort/to-nitroarylacetonitriles into indoles. Alkylation of such nitriles with allyl or benzyl halides followed by treatment of the compounds obtained with basic agents results in a multistep transformation, which is likely to proceed via intermediate nitrosoarenes, to produce 1-hydroxyindoles. For instance, alkylation of ort/io-nitroarylacetonitriles with 3-phenylallyl bromide gives the compounds that in the presence of chlorotri-methylsilane and triethylamine undergo cyclization into 3-cyano-l-hydroxy-2-vinylindoles (Scheme 70) [188]. Presumably, this reaction proceeds via 0-silylation of the nitronate anion and 1,5-elimination of trimethylsilanol from the intermediate trimethylsilyl nitronate, followed by cyclization and a hydrogen shift. 

The methyl group of some heterocycles may be converted into the hydroxy-imino derivative (15) by reaction with pentyl nitrite. On dehydration with acetic anhydride, 2-cyano-l-methylbenzimidazole was obtained but if an excess of the reagent is present, acetoxylation of the benzene ring was claimed to occur. 2-Cyanobenzothiazole was similarly prepared [66]. 

Label all a- and fi-bonds for each functional group in (a) 4 hydroxy-5-methyl-2-hexanone, (b) 2-cyano-l-phenyl-l-propanoI, and (c) 2-methyl-6-pbenyl-3-hexanone. 

It is believed (54IZV47 72JPR353) that in the first stage the intermediate 282 is formed due to the addition of the CH acid to the enamine moiety with subsequent elimination of amine. The enol form of the intermediate 282 undergoes cyclization in two fashions, depending on the nature of substituent X. In the case of the ester (X = OMe) the attack is directed to the cyano group to form substituted 3-methoxycarbonyl-I//-pyridin-2-one (283) or its tautomer (2-hydroxy-3-methoxycarbonylpyridine). With the amide (X = NH2) intramolecular condensation leads to 3-cyano-l//-pyridin-2-one and its hydroxy tautomer (284). 

A theoretical study based on PM3 frontier molecular orbital (FMO) and potential energy surface (PES) analysis at the RHF/6-31-I-G level was performed to examine the reaction of l-amino-2-ethoxycarbonylpyridinium mesitylenesulfonate and acrylonitrile in the presence of Hiinig s base leading to the formation of 3-cyano-4-hydroxy-l,2-dihydropyrido[l,2-ft]pyridazi-nium inner salt (54) (99JOC9001). The calculations indicated that both the... 

The nucleophilic alkenoylation of a-phenyl-substituted aldehydes and ketones with (methyl-substituted) [l-cyano-l-(trimethylsilyloxy)-2-propenyl]lithium proceeds with good 1,2-induction to afford the j> i-hydroxy ketones109. 

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