1-Isoquinolone

Vinyl chloride forms a photo [2 + 2] cycloadduct with 1-isoquinolone [491-30-5] and its /V-methyl derivative (57). 

Phthalide enolates 4 add to Schiff bases to produce intermediate adducts 5 which cyclize to mixtures of cis- and Rcws-isoquinolones 6 and 724. The er.y-product predominates consistently by — 2 1 over a series of nonenolizable arylintines. 

The reaction is essentially that described by the submitters.8 The procedure illustrates a convenient method for the synthesis of a type of lactone which could serve as an important intermediate in the synthesis of isoquinolones, tetrahydroisoquinolines, and isoquinoline alkaloids Several analogous and closely related lactones have been reported. 

The parent, unsubstituted isochromanone has been caused to react with a variety of aromatic amines to prepare Ar-substituted 1,4-dihydro-3(2.ff)-isoquinolones,4 and with amines to give amides.5 The 6,7-methylenedioxy-3-isochromanone was an intermediate in the synthesis of protopine and its allied alkaloids,6 and for the synthesis of the berberine ring system.7 The 6-methoxy analog was prepared as a potential intermediate in a camptothecin synthesis8 and 8-methoxy-4,5,6,7-tetramethyl-3-isochromanonc was an intermediate in the synthesis of sclerin.9 The compound herein described was the basis of a facile synthesis of ( l )-xylopmins,10 and its reaction with hydrazine has been reported.11... 

Cyclization of allene 71 using a catalyst system comprising 10 mol % Pd(OAc)2, 20 mol % PPhj and K COj in the presence of amine 72 affords isoquinolone 73 <95CC1903>. 

Esters of 2-(2-methylphenyl)hydrazinecarboxylic acids were metaUated with excess LDA, and the resulting polyanion intermediates were condensed with aromatic esters followed by acid cyclization to give 3-substituted l(2f/)-isoquinolones 76 <96SC(26)1763>. 

A new synthetic route to 2-alkyl-4-aryl-l(2ff)-isoquinolones 77 involves the base promoted cyclization of phosphorylated o-aroylbenzamides <96T(52)4433>. 

Additional combinatorial variation sites allow the heterocyclic self-assembly units. Thus, it has been shown that heterocycles 11 and 14-17 can serve as A-analogous donor-acceptor ligands self-assembling with the T-analogous acceptor-donor ligands isoquinolone 12 and 7-azaindole 18 (Scheme 30) [92]. All combinations form the heterobidentate ligands exclusively upon simple mixing in the presence of a transition metal salt (proven by X-ray, NMR). 

Table 3 4x4 ligand matrix of aminopyridine (4a-d)/isoquinolone (5a-d) derived self-assembled bidentate ligands in the [Rh]-catalyzed hydroformylation of l-octenea... 

Recent patent disclosures reveal efforts to optimize within this template. The amide moiety has been cyclized to give dihydroisoquinolone inhibitors such as 9 and 10 [57]. Using various mono- and bicyclic core structure scaffolds, the amide has also been constrained in isoquinolone,... 

In a facile and rapid stereoselective, three-component, one-pot reaction, a series of cis-isoquinolonic acids 132 were synthesized using silica supported sulfuric acid to catalyze the reaction between homophthalic anhydride 133 with different aldehydes 134 and amines 135. This three-component cyclocondensation offers a variety of advantages including high yields, easy experimental work-up, and the use an inexpensive, non-toxic, readily available, and recyclable catalyst <06JHC187>. 

More than 55 alkaloids have been isolated from peyote. Mescaline (3,4,5-trimethoxy-j8-phenethylamine) is the primary psychoactive alkaloid of the peyote cactus, and by far the one that has been most studied (figure 9.6). These may be categorized into phenethylamines (including mescaline), isoquinolones, and Krebs acid conjugates. See table 9.2 for a partial list of peyote alkaloids. 

Substitution with displacement of halide occurs readily at C-1 and much less readily at C-3 for the same reasons, i.e. the loss of benzene resonance if C-3 is attacked. 1-Isoquinolone exists completely in the... 

In the case of 489, the product 490 cyclizes to the isoquinolone 491, and the amide substituent is a required part of the target molecule" . However, it frequently occurs that the amide substituent is not required in the final product, and the acid-sensitive alkenyl substituent of 492 has been used as a solution to the problem of cleaving a C—N bond in the product (Scheme 193) ° °. Weinreb-type amides 493 can also be laterally lithiated, and the methoxy group removed from 494 by TiCU" . Hydrazones similarly can be laterally lithiated and oxidatively deprotected. ... 

Enamine carbaldehyde 76 (Scheme 20) by sequential photochemical cycloaddition and iminium ion-propargylsilane cyclimtion furnishes allenes 77a-c in good yield and with high diastereoselectivity (92X2081). (Gas chromatographic fR values and thin-layer chromatographic Rp values have been reported.) Radical cyclization of ca-iodoalkyl isoquinolone 78a under... 

Isoquinolone 200 is the result of a palladium-catalyzed carboxamida-tion/aldol condensation cascade of o-iodophenylacetic ester, caprolactam, and carbon monoxide (08OL4987). 

The ionic liquid [BMIM]BF4 was found to efficiently catalyze the three-component coupling reactions of aldehydes, amines, and homophthalic anhydride under ambient conditions to give the corresponding c/ -isoquinolonic acids in excellent yields with... 

A novel route to ( )-0-methylthalisopavine (26) involves the oxidation of the properly substituted tetrahydro-3-isoquinolone of type 129 with vanadium oxy-trifluoride to furnish bridged lactam 130. Compound 130 was then reduced to the racemic isopavine alkaloid 26 in an overall yield of 4.4% (Scheme 26) 136). 

In a related type of reaction, the styryl isocyanates, readily available by Curtius rearrangement of cinnamoyl azides, undergo thermal cyclization to l-isoquinolones in good yield (equation 34) the reaction can also be carrried out using Friedel-Crafts catalysts. 2,3-Dihydro-4( 1//)- isoquinolones are obtained by Dieckmann cyclization of N- (o- carbalkoxy-benzyl)glycine ester derivatives (equation 35). The same reaction has been used for the synthesis of a range of non-aromatic heterocycles (equations 36 and 37). 

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