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

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

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

2,4,5-Trisubstituted oxazoles <b>6</b> were unexpectedly prepared from a tandem reaction of vinyliminophosphorane <b>3</b> with various acyl chlorides in a one-pot 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 <b>2</b>, aldehyde <b>3</b>, acid <b>4</b>, and isocyanide <b>5</b> produced the benzimidazoles <b>8</b> in moderate to good yields via a sequential Ugi condensation and catalytic aza-Wittig in the presence of a catalytic amount of phospholene oxide

Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles by a Sequential Aza-Wittig/Michael/Isomerization Reaction

Carbodiimides <b>4</b>, obtained from aza-Wittig reactions of iminophosphorane <b>3</b> 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 <b>7</b> in good yields. However, 4-acylimidazoles <b>11</b> 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 <b>10</b>

One-Pot Synthesis of Indoles by a Sequential Ugi-3CR/Wittig Reaction Starting from Odorless Isocyanide-Substituted Phosphonium Salts

A new one-pot preparation of indoles by a Ugi-3CR/Wittig sequence has been developed. The reaction of odorless isocyanide-substituted phosphonium salt <b>5</b>, aldehyde <b>6</b>, and amine <b>7</b> produced the indoles <b>9</b> in 45–82% yields via a sequential Ugi-3CR/Wittig reaction in the presence of H₃PO₄ and solid K₂CO₃, respectively

Synthesis of 2,3-Dihydro‑1<i>H</i>‑2-benzazepin-1-ones and 3<i>H</i>‑2-Benzoxepin-1-ones by Isocyanide-Based Multicomponent Reaction/Wittig Sequence Starting from Phosphonium Salt Precursors

A one-pot synthesis of multisubstituted 2,3-dihydro-1<i>H</i>-2-benzazepin-1-ones and 3<i>H</i>-2-benzoxepin-1-ones by an I-MCR/Wittig sequence was developed. The reaction of phosphonium salt <b>3</b>, arylglyoxals <b>4</b>, amine <b>5</b> (or without), and isocyanide <b>6</b> produced the 2,3-dihydro-1<i>H</i>-2-benzazepin-1-ones <b>8</b> or 3<i>H</i>-2-benzoxepin-1-ones <b>10</b> in good yields via a sequential Ugi or Passerini condensation and intramolecular Wittig reaction in the presence of NEt₃

One-Pot Synthesis of Polysubstituted Imidazoles via Sequential Staudinger/aza-Wittig/Ag(I)-Catalyzed Cyclization/Isomerization

A new one-pot preparation of polysubstituted imidazoles by a Staudinger/aza-Wittig/Ag­(I)-catalyzed cyclization/isomerization has been developed. The easily accessible propargylazide derivatives reacted with triphenylphosphine, isocyanates, and amines sequentially to produce the fully substituted imidazoles in good overall yields in the presence of catalytic amount of AgNO₃/DMAP

Unexpected Synthesis of 5,6-Dihydropyridin-2(1<i>H</i>)‑ones by a Domino Ugi/Aldol/Hydrolysis Reaction Starting from Baylis–Hillman Phosphonium Salts

A one-pot synthetic approach to 5,6-dihydropyridin-2­(1<i>H</i>)-ones has been developed using a domino process involving Ugi, aldol, and hydrolysis reactions, starting with Baylis–Hillman phosphonium salts, primary amines, isocyanides, and arylglyoxals

Unexpected Synthesis of 5,6-Dihydropyridin-2(1<i>H</i>)‑ones by a Domino Ugi/Aldol/Hydrolysis Reaction Starting from Baylis–Hillman Phosphonium Salts

A one-pot synthetic approach to 5,6-dihydropyridin-2­(1<i>H</i>)-ones has been developed using a domino process involving Ugi, aldol, and hydrolysis reactions, starting with Baylis–Hillman phosphonium salts, primary amines, isocyanides, and arylglyoxals

Synthesis, Fungicidal Activity, and Sterol 14α-Demethylase Binding Interaction of 2‑Azolyl-3,4-dihydroquinazolines on Penicillium digitatum

A series of new 2-azolyl-3,4-dihydroquinazolines <b>6</b> was synthesized by direct cyclization of imidazole or 1,2,4-triazole with carbodiimides <b>4</b>, which were obtained from aza-Wittig reaction of iminophosphorane <b>3</b> with isocyanate. The preliminary bioassay results demonstrated that most of the 2-imidazolyl-3,4-dihydroquinazolines <b>6a</b>–<b>6i</b> exhibited good to significant fungicidal activity against Penicillium digitatum, whereas 2-triazolyl-3,4-dihydroquinazolines <b>6j</b>–<b>6t</b> exhibited low fungicidal activity. Some of the 2-imidazolyl-3,4-dihydroquinazolines <b>6a</b>–<b>6i</b> also exhibited strong binding interaction with the cytochrome P450-dependent sterol 14α-demethylase (CYP51). For example, compound <b>6e</b> showed the best fungicidal activity against <i>P. digitatum</i> with IC₅₀ = 4.14 μg/mL and the best CYP51 binding activity with <i>K</i>_d = 0.34 μg/mL, both superior to those of the agricultural fungicide triadimefon