Formyl nitrile

The fragmentation mode was observed mostly in electron-rich cyclic alkenes, including steroids, which afforded co-formyl nitriles [89] ... 

There has been a number of developments in the use of salicylaldehydes as precursors of both chromenes and chromans. Alkenes activated by acyl, formyl, nitrile and phenylsulfonyl groups react with 2-hydroxybenzaldehydes and 2-hydroxy-1-naphthaldehyde under Bayliss-Hillman conditions to yield 3-substituted chromenes via the in situ dehydration of the initially formed chroman-4-ol <02JCS(P1)1318>. In like manner, P-nitrostyrenes yield 2- and 2,2-substituted derivatives of 3-nitrochromenes <02H(57)1033>. A simple route to 2-phenyl-2H-chromenes starting from salicylaldehyde and utilising a Pd(0)-catalysed cyclisation of an allylic acetate has been described <02SC3667>. 

However, one advantage does result. It is usually possible by inspection of a 13C spectrum to recognize the nuclei that do not bear protons by their low intensity (peaks 1 and 2 in Fig. 5.1 h). The common spin-lattice relaxation mechanism for 13C results from dipole-dipole interaction with directly attached protons. Thus, non-protonated carbon atoms have longer Tx relaxation times, which together with little or no NOE, results in small peaks. It is therefore often possible to recognize carbonyl groups (except formyl), nitriles, nonproton-ated alkene and alkyne carbon atoms, and other qua-ternaryt carbon atoms readily. 

Hydrocyanic acid, formyl nitrile, prussic acid. 

Other carbonyl compounds are within the scope of the reaction ketones give amides, and aldehydes yield nitriles and formyl derivatives of amines ... 

The reaction proceeds via die hydrolysis of nitrile groups to an amide. The amides may also be A-formyl amines, which react with acid groups whereby volatile formic acid is shipped10 ... 

Hydroxy-2-formyl- -lacton 360 4-Hydroxy- -nitril 604 4-Hydroxy-3-oxo- -methylester 204 4-Hydroxy-4-phenyl- -lacton... 

The Stille coupling reaction is very versatile with respect to the functionality that can be carried in both the halide and the tin reagent. Groups such as ester, nitrile, nitro, cyano, and formyl can be present, which permits applications involving masked functionality. For example, when the coupling reaction is applied to l-alkoxy-2-butenylstannanes, the double-bond shift leads to a vinyl ether that can be hydrolyzed to an aldehyde. 

Carbon monoxide, hydrogen cyanide, and nitriles also react with aromatic compounds in the presence of strong acids or Friedel-Crafts catalysts to introduce formyl or acyl substituents. The active electrophiles are believed to be dications resulting from diprotonation of CO, HCN, or the nitrile.64 The general outlines of the mechanisms of these reactions are given below. 

The reaction of 3,4-diacyl-l,2,5-oxadiazole 2-oxides (furoxans) with activated nitriles in ionic liquids and in ethanol unexpectedly resulted in 3-acyl-4-acylamino-l,2,5-°xadiazoles (furazans) <2003MC230>. 3-Formyl-4-phenyl-l,2,5-oxadiazole Ar-oxide 105 is a good precursor for the synthesis of functional substituted furoxans (Scheme 28) <1999JME1941, 2000MOL520, 2000JFA2995>. 

It is of course possible to name individual radialenes according to IUPAC rules [e.g. per(methylene)cycloalkanes 1-4]. However, the descriptiveness of the term radialene may some day pave its way into the official nomenclature. For substituted [ ]radialenes we have proposed1 a pragmatic numbering system, in which an inner ring is numbered first, followed by an outer ring . The numbering of substituents should follow IUPAC rules. Thus, the hydrocarbon 7 is 4,4-diethyl-5,5-dimethyl[3]radialene, the ester 8 should be called 7-methoxycarbonyl-5,5-dimethyl[4]radialene, the nitrile 9 which can exist in four diastereomeric forms is (6Z,7Z)-6-cyano-5,5,7-trimethyl[4]radialene and the difunctionalized [5]radialene 10 is (7 ,6Z)-7-bromo-6-formyl-6-methyl[5]radialene. 

Formyl C-glycosides, prepared in three steps via the thiazole-based formy-lation of sugar lactones are readily condensed with hydroxylamine to give the corresponding oximes. The latter are the precursors of glycosyl nitrile oxides via the N-bromosuccinimide method (41). 

Aldehydo nitriles are readily available and can be used to prepare 4-amino-6-unsubstituted pyrimidines carrying one or more substituents in any of the other positions. Equivalents of the formyl group are also often used, for example, a 3-ethoxy-, 3-amino-, or 3-haloacrylonitrile. Most syntheses with /3-keto nitriles are carried out with equivalents thereof Such equivalents are /3-substituted /3-alkoxy-, /3-amino-, or /3-haloacrylonitriles. /3 -Ester nitrile reactions are also well established. Malononitriles and substituted malononitriles react readily with thiourea and N-substituted thioureas in refluxing ethanolic sodium ethoxide to form pyrimidine-4,6-diamines. An example is the reaction of N2-malononitrile 680 with N2-thiourea 681 to give N4- 4,6-diamino-2-(l//)-pyrimidinethione 682 which was then used in the synthesis of Ns-labeled adenine derivatives <2001JOC5463>. 

Transformation of both the ester and nitrile derivatives 726 or 727 into pyrano[2,3-t7 pyridazines 728 or 729, respectively, by treatment with dilute HCl at room temperature involved nucleophilic displacement of the morpholine group by the hydroxyl group with an acidic hydrolysis followed by intramolecular iminolactonization and then hydrolysis of the formed imino group to a carbonyl group. Compounds 726 and 727 were prepared by Vilsmeier-Haack formylation of 2-methyl-5-morpholino-3(2/7)-pyridazinone 724 followed by condensation of the resulting product 725 with either ethyl a-cyanoacetate or malononitrile in EtOH (Scheme 34) <1994H(37)171>. 

Table9. H- and13C-NMR Analysis of Noe Lactols42 of Alcohols Containing Phenyl, Nitrile, Ethynyl and Formyl Groups Directly Bound to a Secondary Alcohol Function (First Value B-Type, Second Value A-Type d)...

Table 9 shows different chemical shifts for the three depicted most useful hydrogens and the respective carbons of selected lactols derived from secondary alcohols containing phenyl, nitrile, ethynyl and formyl groups directly bound to the stereogenic center. 

Zu Imidazolen ohne Hetero-Substituenten in 5-Stellung fuhrt die folgende Variante Das oc-(Alkoxymethyliden-amino)-carbonsaure-nitril wird mit Natriumethanolat und Ameisensaure-ethylester zum Enolat des entsprechenden a-Formyl-Derivates kondensiert und dieses dann in einer Eintopfsynthese mit Ammoniumsulfat zum 4(5)-Cyan-imidazol, z.B. 4(5)-Cyan-2-phenyl-imidazol bzw. 2-Benzyl-4(5)-cyan-imidazol cyclisiert250,251. 

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