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A novel metal-free synthesis of 3-substituted isocoumarins through a sequential O-acylation/Wittig reaction has been established. The readily accessible (2-carboxybenzyl)-triphenylphosphonium bromide and diverse chlorides produced various 1H-isochromen-1-one in the presence of triethylamine, employing sequential O-acylation and an intramolecular Wittig reaction of acid anhydride. Reactions using these facile conditions have exhibited high functional group tolerance and excellent yields (up to 90%). Moreover, the fluorescence properties of isocoumarin derivatives were evaluated at the theoretical and experimental levels to determine their potential application in fluorescent materials. These derivatives have good photoluminescence in THF with a large Stokes shift and an absolute fluorescence quantum yield of up to 14%. [ABSTRACT FROM AUTHOR]

A new one-pot synthesis of 3-(1,2,3,4-tetrahydroisoquinolin-1-yl)-isoquinolin-1(2 H)-ones by DEAD-promoted oxidative Ugi–-Wittig reaction was developed. The sequential reactions of (2-carboxybenzyl)triphenylphosphonium salts, isocyanides, and N -aryl-1,2,3,4-tetrahydroisoquinolines produced 3-(1,2,3,4-tetrahydroisoquinolin-1-yl)-isoquinolin-1(2 H)-ones in moderate to good overall yields in the presence of DEAD and Et3 N. [ABSTRACT FROM AUTHOR]

A new efficient synthesis of pyrrolidin-2-ones via sequential Wittig reaction/nucleophilic addition/cyclization was developed. The Wittig reaction of the phosphoranes with isocyanates produced ketenimine intermediates that were then treated with primary amines to give amidines, which were treated with catalytic sodium alkoxide to give 2-imino-5-oxopyrrolidine-3-carboxylates in good yields. [ABSTRACT FROM AUTHOR]

The catalytic intramolecular Wittig reactions of carbonyl-containing bromides are reported. The R3PO byproducts participate in the catalytic cycle; therefore, the Wittig reaction can be accomplished with only a catalytic amount of organophosphorus reagent. The reaction has also been applied to the efficient and selective synthesis of isoquinolin-1(2H)-ones, indoles, 2,3-dihydro-1H-2-benzazepin-1-ones, benzofurans, and 1,2-dihydroquinolines with a catalytic amount of phosphine oxide (0.1 equiv.) and a tetramethyldisiloxane/titanium isopropoxide [TMDS/Ti(OiPr)4] reductant system (yields: 35-88 %). [ABSTRACT FROM AUTHOR]

7-Benzyl-5,6,7,8-tetrahydropyrido[4′,3′:4,5]thieno[2,3- d]pyrimidin-4(3 H)-ones were synthesized by base catalyzed reactions of nucleophilic reagents (aliphatic amines, alcohols or phenols) with carbodiimides 4, which in turn were obtained by the aza-Wittig reaction of iminophosphoranes 3 with aromatic isocyanates. [ABSTRACT FROM AUTHOR]

2-Dialkylamino-4H-imidazolin-4-ones 6 were rapidly synthesized by a solution-phase parallel synthetic method, which includes Aza-Wittig reaction of iminophosphorane 3 with aromatic isocynate to give carbodiimide 4 and subsequent reaction of 4 with various aliphatic secondary amine in a parallel fashion. [ABSTRACT FROM AUTHOR]

A library of imidazolin-4-ones has been synthesized �using poly(ethylene glycol) (PEG) as soluble polymer support. The imidazolin-4-ones 6 or 7 were synthesized effectively by reaction of primary amine with PEG-supported carbodiimides 4, which were obtained from aza-Wittig reaction of PEG-supported iminophosphoranes 3 with isocyanates. [ABSTRACT FROM AUTHOR]

A new facile preparation of furan-2(3 H)-ones and 2,3,5-trisubstituted furans by a sequential O-acylation/Wittig(/O-acylation) reaction has been developed. The easily accessible 2-(triphenylphosphoranylidene)-succinic acid 1-ester 3 reacted with acid chloride produced furan-2(3 H)-ones 4 in good yields in the presence of DMAP via sequential O-acylation and intramolecular Wittig reaction of acid anhydride. Subsequently, the 2,3,5-trisubstituted furans 5 were prepared from furan-2(3 H)-ones 4 and diverse aryl chlorides in presence of triethylamine through further O-acylation. Image 1 [ABSTRACT FROM AUTHOR]

An efficient preparation of multisubstituted benzimidazoles and quinoxalin-2(1 H )-ones by Ugi 4CC/aza-Wittig sequence was developed. The 2-azidobenzenamines, obtained from C H activation of aromatic amine precursors, reacted with aldehydes, acids, and isocyanides to produce Ugi products, which were transformed to the benzimidazoles or quinoxalin-2(1 H )-ones in moderate to good yields in further reaction with triphenylphosphine. [ABSTRACT FROM AUTHOR]

Abstract: A series of 1,2,4-trisubstituted imidazoles 5 were synthesized efficiently by a tandem aza-Wittig/1,5-electrocyclic ring-closure reaction of vinyliminophosphoranes 3 with aldehydes. Reactions of 5s,t with triphenylphosphine produced iminophosphoranes 7. A tandem aza-Wittig reaction of iminophosphorane 7 with isocyanate generated imidazo[1,2-c]quinazolines 9 in high yields. [Copyright &y& Elsevier]

Abstract: A series of 2,3,4-trisubstituted 3,4-dihydroquinazoline 3 was prepared by intramolecular aza-Wittig reaction of amide carbonyl groups with methyldiphenyl iminophosphorane, which was obtained from a Ugi 4CC/Staudinger sequence. Further intramolecular Heck reaction of 3d′–g′ in the presence of catalytic amount of Pd(OAc)2 gave 6,12-dihydroindolo[2,1-b]quinazolines 4a–d in good yields. [Copyright &y& Elsevier]

Abstract: The carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aromatic isocyanates, reacted with amines in the presence of a catalytic amount of RO−Na+ to give the 1,2,9-trisubstituted 1,9-dihydro-6H-purin-6-ones 6 in good yields. Compound 6 exhibited cytotoxicity against various cancer cells. For example, compounds 6b showed the best inhibition activities against KB, HepG2 and OVCAR3 with IC50 9.5, 20.4 and 10.0μM. [Copyright &y& Elsevier]

Passerini or Ugi condensations, coupled with an intramolecular Wittig reaction give access to the title compounds. [ABSTRACT FROM AUTHOR]

Title compounds (V) and (VII) are synthesized in a facile one-pot procedure by a new sequential Ugi 4CC/Staudinger/aza-Wittig reaction. [ABSTRACT FROM AUTHOR]

Abstract: Dihydropyrimidinone azides 1, obtained from trimethylsilyl chloride-catalyzed Biginelli reaction of 2-azidobenzaldehyde, ethyl acetoacetate, and urea (or thiourea) at room temperature, reacted with triphenylphosphine to give iminophosphorane 2. A tandem aza-Wittig reaction of iminophosphorane 2 with isocyanate, acyl chloride or CS2 in the presence of K2CO3 or NEt3 generated pyrimido[1,6-c]quinazolin-4-ones 4, 6 or 8 in moderate to good yield. [Copyright &y& Elsevier]

Abstract: α-Acyloxy-carboxamide azides 1, obtained from Passerini reaction of easily accessible o-azidobenzaldehyde with isocyanides and carboxylic acids, reacted with triphenylphosphine to give various 4-aminocarbonyl substituted 4H-1,3-benzoxazines 3 in moderate to high yields via sequential Staudinger and intramolecular aza-Wittig reaction. However, α-hydroxy carboxamide azides 5 were obtained in moderate yields when pyruvic acid was used in the Passerini reaction. Further sequential reaction of azides 5 with triphenylphosphine and isocyanates produced 2-amino-4-aminocarbonyl substituted 4H-1,3-benzoxazines 8 via a tandem Staudinger/aza-Wittig/heterocumulene-mediated annulation. [Copyright &y& Elsevier]

Abstract: The carbodiimides 2, obtained from aza-Wittig reactions of iminophosphorane 1 with aromatic isocyanates, reacted with ammonia to give ethyl 3,4-dihydro-6-methyl-4-oxo-2-arylamino-furo[2,3-d]pyrimidine-5-carboxylate 3. Further reaction of 3 with POCl3 and various amines generated ethyl 4-alkylamino-2-arylamino-6-methyl-furo[2,3-d]pyrimidine-5-carboxylate 5 in good yields. Their structures were confirmed by 1H NMR, EI-Ms, IR and elemental analysis. Compound 5b was further analyzed by single crystal X-ray diffraction. Compound 5 exhibited cytotoxicity against two lung cancer cell lines. For example, compound 5a showed the best inhibition activities against A459 with IC50 0.8μM. [ABSTRACT FROM AUTHOR]

A new one-pot four-component preparation of polysubstituted thiazoles by a cascade Ugi/Wittig cyclization has been developed. The four-component reactions of the odorless isocyano(triphenylphosphoranylidene)acetates 1 , aldehydes 2 , amines 3 and thiocarboxylic acids 4 produced 2,4,5-trisubstituted thiazoles 5 in moderate to good yields in the presence of triethylamine. The two-component reactions between isocyano(triphenylphosphoranylidene)acetates 1 and thiocarboxylic acids 4 in the presence of triethylamine provided the corresponding 4,5 - disubstituted thiazoles 6 in good yields as well. Image 1 • One-pot four-component reactions. • Mild reaction conditions. • Good yields. [ABSTRACT FROM AUTHOR]

Besides for the synthesis of the drug methaqualone (IVb) and the natural product deoxyvasicinone (Xa) the method is used as the key step in the preparation of the alkaloid (S)-vasicinone. [ABSTRACT FROM AUTHOR]

Ugi-type four-component reaction allows the synthesis of 2-azidoacrylamides, which are further converted into the title products via sequential Staudinger and intramolecular aza-Wittig reaction. [ABSTRACT FROM AUTHOR]