Ming-Wu Ding

Synthesis of 1,2,4,5-tetrasubstituted imidazoles by a sequential aza-Wittig/Michael/isomerization reaction.

Carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aryl isocyanates, reacted with secondary amines in the presence of a catalytic amount of sodium alkoxide to give 1,2,4,5-tetrasubstituted imidazoles 7 in good yields. However, 4-acylimidazoles 11 were obtained, as phenols were used in the presence of a catalytic amount of potassium carbonate due to further air oxidation of the expected products 10.

Efficient Regioselective Synthesis of Indole N-Carboximidamides and N-Carboximidoates by a Sequential Aza-Wittig/Ag(I)-Catalyzed Cyclization

An efficient Ag(I)-catalyzed regioselective cyclization of (2-alkynylphenyl)guanidine or (2-alkynylphenyl)isourea to indole N-carboximidamides or N-carboximidoates has been developed. The approach has the advantages of high regioselectivity, mild reaction conditions, easily accessible starting materials, and good yields.

Iminophosphorane-mediated efficient synthesis of new tricyclic 3,5-dihydro-1,2,3-triazolo[4,5- d ]-1,2,4-triazolo[1,5- a ]pyrimidin-9-ones

The carbodiimides 2, obtained from aza-Wittig reactions of iminophosphorane 1 with aromatic isocyanates, reacted with hydrazine to give selectively 6-amino-7H-1,2,3-triazolo[4,5-d]pyrimidin-7-ones 5. Compounds 5 were further transformed to iminophosphoranes 6 by reaction with triphenylphosphine, hexachloroethane and triethylamine. A tandem aza-Wittig reaction of iminophosphorane 6 with isocyanate or acyl chloride generated previously unreported 3,5-dihydro-1,2,3-triazolo[4,5-d]-1,2,4-triazolo[1,5-a]pyrimidin-9-ones 10 or 12 in satisfactory yield. X-ray structure analysis of 10 g verified the proposed structure and the reaction selectivity.

Unexpected Synthesis of 2,4,5-Trisubstituted Oxazoles via a Tandem Aza-Wittig/Michael/Isomerization Reaction of Vinyliminophosphorane

2,4,5-Trisubstituted oxazoles 6 were unexpectedly prepared from a tandem reaction of vinyliminophosphorane 3 with various acyl chlorides in a one-pot fashion.

An Efficient Synthesis of 2-Alkylthio- 5-phenylmethylidene-4H-imidazolin-4-ones

Abstract 2-Alkylthio-5-phenylmethylidene-4H-imidazolin-4-ones 5 were synthesized by S-alkylation of thioimidazolinones 4, which were obtained via cyclization of carbodiimides 2 with Na2S/HOAc. The direct reaction of carbodiimides 2 with butylthiol could not give 2-butylthio-4H-imidazolin-4-ones 3.

Synthesis and fungicidal activities of 4H-imidazolin-4-ones containing sulfur substituent

4H-Imidazolin-4-ones 3 and 4 were synthesized respectively by base catalytic reactions of 4-methylthiophenol or phenthiol with carbodiimides 2 , which were obtained via aza-Wittig reaction of iminophosphorane 1 with aromatic isocyanates. 3 and 4 exhibited good fungicidal activity against Pellicularia sasakii.

A Rapid Parallel Synthesis of 2-Dialkylamino-4H-imidazolin-4-ones

Abstract 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.

One-Pot Synthesis of Multisubstituted Benzimidazoles via Sequential Ugi and Catalytic Aza-Wittig Reaction Starting from 2-Aminobenzoyl Azides

A simple and one-pot synthesis of multisubstituted benzimidazoles by a Ugi 4CC/catalytic aza-Wittig sequence was developed. The reaction of 2-aminobenzoyl azide 2, aldehyde 3, acid 4, and isocyanide 5 produced the benzimidazoles 8 in moderate to good yields via a sequential Ugi condensation and catalytic aza-Wittig in the presence of a catalytic amount of phospholene oxide.

Improved Synthesis of 2‐(3H)Benzothiazolethiones under Microwave Irradiation

Abstract 2‐(3H)Benzothiazolethiones (2‐mercaptobenzothiazole) are prepared by an improved method, which utilizes microwave‐assisted cyclization of the corresponding ortho‐haloanlines with potassium O‐ethyl dithiocarbonate. By using microwave irradiation, the relative reactivity of 2‐chloroanilines was greatly improved to the same level as that of 2‐fluoroanilines and 2‐bromoanilines.

Efficient synthesis and biological evaluation of some 2,4-diamino-furo[2,3-d]pyrimidine derivatives

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 POCl(3) 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 (1)H 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 IC(50) 0.8μM.