Synthesis of 1‐acyl‐2‐oxo‐3‐pyrrolidinecarbonitriles by the reaction of 2‐acylamino‐4,5‐dihydro‐3‐furancarbonitriles with sodium iodide

The reaction of 2‐acylamino‐4,5‐dihydro‐3‐furancarbonitriles 1 with sodium iodide in N,N‐dimethyl‐formamide gave the corresponding 1‐acyl‐2‐oxo‐3‐pyrrolidinecarbonitriles 2 in good yields. Successive treatment of 1 with titanium(IV) chloride and potassium carbonate resulted in the formation of N‐acyl‐1‐cyanocyclopropanecarboxamides 4 . The same compounds 2 were also obtained by treatment of 4 with sodium iodide. The starting compounds 1 were synthesized by the reaction of 2‐amino‐4,5‐dihydro‐3‐furan‐carbonitrile with acyl chlorides in pyridine.     

Synthesis and Some Reactions of 2‐Acyl‐2‐alkyl‐1,3‐dithiolane 1,1‐Dioxides

The selective formation of optically active 2‐acyl‐2‐alkyl‐1,3‐dithiolane 1,1‐dioxides from the corresponding 2‐acyl‐2‐alkyl‐1,3‐dithiolane 1‐oxides, by reaction with OsO₄ and NMO in acetone, is reported. These compounds underwent stereoselective reactions at the carbonyl group of the acyl group with organometallic reagents. These reactions were completely regioselective, and no attack at either of the S‐atoms was observed, unlike similar reactions with the corresponding sulfoxides. The nature of the metal atom had a direct effect upon the configuration of the product alcohols.     

Old Selenium Heterocycles Revisited: Synthesis,Spectroscopic, and Structural Characterization of N‐Acyl‐1,3‐selenazol‐2(3H)‐imines and 5‐Acyl‐1,3‐selenazol‐2‐amines from Acylselenourea Derivatives

A series of five‐membered selenium heterocycles was prepared from the reaction of various selenoureas and phenacyl bromides. In the case of 1‐acyl‐3‐arylselenoureas N‐acyl‐1,3‐selenazol‐2(3H)‐imines are formed, whereas the analogous reaction with 3,3‐disubstituted 1‐acylselenoureas affords 5‐acyl‐1,3‐selenazol‐2‐amines. The compounds were characterized by NMR spectroscopy and mass spectrometry. In addition, the proposed structures were unambiguously confirmed by X‐ray diffraction studies.     

Palladium‐Catalyzed Carbonylative α‐Arylation of 2‐Oxindoles with (Hetero)aryl Bromides: Efficient and Complementary Approach to 3‐Acyl‐2‐oxindoles

An efficient Pd‐catalyzed carbonylative α‐arylation of 2‐oxindoles with aryl and heteroaryl bromides for the one‐step synthesis of 3‐acyl‐2‐oxindoles has been developed. This reaction proceeds efficiently under mild conditions and is complementary to the more common oxindole forming reactions. The transformation only requires a mild base and provides good to excellent yields even with heteroaromatic substrates. Employing a near stoichiometric amount of ¹³COgen, the methodology was easily extended to [¹³C] acyl labeling. The general applicability of the reaction conditions was demonstrated in the synthesis of a structure related to the pharmaceutically active 3‐acyl‐2‐oxindoles, tenidap.     

Unusual behaviour of N‐cinnamoyl‐2‐hydroxy‐2‐(trifluoromethyl)‐arylethylamines in pictet‐gams cyclization. Synthesis of 2‐styryl‐5‐aryl‐5‐trifluoromethyl‐2‐oxazolines

Cyclization of N‐acyl‐2‐hydroxy‐2‐(trifluoromethyl)arylethylamines 4 under Pictet‐Gams conditions afforded 2‐oxazolines 5 instead of the expected isoquinolines 6 . The effect of the trifluoromethyl group on the result of the reaction is discussed.     

用聚乙二醇简便合成3-取代-1, 2, 3, 4-四氢吡啶并[3, 2-d]嘧啶-2, 4-二酮

用聚乙二醇作为可溶性聚合物载体和相转移催化剂高效简单的合成了1, 2, 3, 4-四氢吡啶并[3, 2-d]嘧啶类化合物。该合成路线为聚乙二醇与2, 3-吡啶二酸酐反应生成聚乙二醇支载的单酯1,接着1被转化成相应的聚乙二醇支载的酰基叠氮2,2经Curtius重排,与胺加成并同时关环给出目标产物,其总产率为84%-88%。     

Chemical transformations of 3‐amino‐2‐quinolones

In order to find new antimalarial drugs, an exploration about the chemical properties of the starting compounds 3‐amino‐6‐chloro‐4‐phenyl‐1H‐quinolin‐2‐one ( 1 ) and 3‐amino‐4‐methyl‐1H‐quinolin‐2‐one ( 2 ) was developed. Acylation with acyl chloride, sulfonyl chloride and acetic anhydride were carried out. Despite a previous report [2], when acetyl chloride or acetic anhydride were assayed on 1 , only the diacetyl derivative 7 was obtained. When this compound was heated at reflux temperature in a mixture of acetic acid and acetic anhydride, it was transformed in the oxazoloquinoline 8 . Further reactions of the acyl derivatives with diazomethane afforded 1‐methylated compounds. Compound 2 gave the imine 16 by condensation with 4‐nitrobenzaldehyde.     

One‐pot solvent‐free synthesis of novel functionalized ethyl 2‐(alkylimino)‐4‐methyl‐3‐(alkanoyl)‐2,3‐dihydrothiazole‐5‐carboxylates

A green and efficient one‐pot two‐step synthesis of ethyl 2‐(alkylimino)‐4‐methyl‐3‐(alkanoyl)‐2,3‐dihydrothiazole‐5‐carboxylates from the reaction between acyl chlorides, ammonium thiocyanate, primary alkylamines, and ethyl 2‐chloroacetoacetae under mild, solvent‐ and catalyst‐free conditions at room temperature is presented. This efficient and straightforward technique gave the expected products in good to high yields in 2–4 hr without the creation of any by‐product in all reactions.     

Synthesis of 3‐Butadienyl‐1‐tosylpyrroles

A pathway for the formation of 3‐butadienyl‐1‐tosylpyrroles from 3‐acyl derivatives via secondary and tertiary 3‐hydroxyalkyl‐1‐tosylpyrroles has been developed. The dehydration of the alcohols intermediates is the crucial step: conditions for high chemo‐ and diastereocontrol are described.     

Preparation of 1,6‐naphthyridine‐2,5(1H,6H)‐diones

Novel method for the synthesis of 3‐acyl‐1,6‐dialkyl‐7‐methyl‐1,6‐naphthyridine‐2,5(1H,6H)‐diones (2) was developed. The reaction of 2‐acyl‐1‐alkylamino‐1‐ethoxyethylenes (1) with acetyl chloride or β‐keto amide 3 with acetyl chloride in the presence of p‐toluenesulfonic acid gave 2 in moderate yield (14‐59% yield).     

Synthesis of 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones VIA lewis acid‐mediated rearrangement of 3‐acyloxypyrazoles

The unusual formation of 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones starting from 3‐acyloxypyrazoles by Fries‐type rearrangement is described. Under normal conditions, acylation of 2,4‐dihydro‐3H‐pyrazol‐3‐ones 1 and 2 with acid chlorides or anhydrides in the presence of triethylamine gave the corresponding 3‐acyloxypyrazoles 3a‐f and 4a‐f . Treatment of 3a‐c and 4a‐f with Lewis acid, e.g. titanium(IV) chloride and tin(IV) chloride, caused migration of acyl groups to afford the corresponding 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones 5a‐c and 6a‐f . Interestingly, the reactions of 3‐acyloxypyrazoles 3e and 3f with tin(IV) chloride provided the corresponding tin(IV) complexes 8e and 8f .     

Synthesis and Herbicidal Activity of Novel 4‐Acyl‐2,5‐disubstituted‐3‐hydroxypyrazoles and 4‐Arylcarbonyl‐3‐substitutedisoxazol‐5‐ones

Two series of novel 4‐acyl‐2,5‐disubstituted‐3‐hydroxypyrazoles 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h and 4‐arylcarbonyl‐3‐substitutedisoxazol‐5‐ones 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i were synthesized by the Scotton–Baumann reaction of 2,5‐disubstituted‐2,4‐dihydro‐pyrazol‐3‐ones 1 or 3‐substituted‐4H‐isoxazol‐5‐ones 6 and various acyl chlorides, followed by the Fries rearrangement in the presence of calcium hydroxide and calcium oxide as the catalyst. Their structures were confirmed by IR, ¹H NMR, mass spectroscopy, and elemental analyses. ¹H NMR indicated that compounds 3 existed in enol forms and compounds 7 in keto configurations. The results of preliminary bioassays showed that some of the title compounds 3 and 7 exhibited moderate to good herbicidal activities against Brassica campestris L. at the concentration of 100 mg/L. Isoxazole compounds 7 showed better herbicidal activity against B. campestris L. than pyrazole compounds 3 did at the concentration of 100 mg/L. Moreover, most of the isoxazole compounds displayed higher herbicidal activity against B. campestris L. than Echinochloa crus‐galli. However, these compounds showed weak herbicidal activities at the concentration of 10 mg/L.     

Formation of Dialkyl 2‐[3‐Alkoxy‐1‐(alkylimino)‐1‐chloro‐3‐oxopropan‐2‐ylidene]hydrazine‐1,1‐dicarboxylates of α‐(Alkoxycarbonyl)imidoyl Chlorides from PhosphineDiazo Ester Zwitterions and Nef‐Isocyanide Adducts

A novel transformation involving phosphine? diazo ester zwitterions (generated from dialkyl azodicarboxylates with Ph₃P) and α‐(alkoxycarbonyl)imidoyl chlorides (prepared from α‐addition of acyl chlorides to alkyl isocyanides) to afford dialkyl 2‐[3‐alkoxy‐1‐(alkylimino)‐1‐chloro‐3‐oxopropan‐2‐ylidene]hydrazine‐1,1‐dicarboxylates in moderate yields, is described.     

Ring closure reactions of 3‐arylhydrazonoalkyl‐quinolin‐2‐ones to 1‐aryl‐pyrazolo[4,3‐c]quinolin‐2‐ones

4‐Hydroxy‐3‐arylhydrazonoalkyl‐2‐quinolones 6 or reactive derivatives such as 3‐arylhydrazonoalkyl‐4‐tosyloxy‐2‐quinolones 7 or 4‐chloro‐3‐arylhydrazonoalkyl‐2‐quinolones 14 , which are obtained via 3‐acyl‐4‐hydroxyquinolones 4, 10 or 3‐phenylarrmomethylene‐quinoline‐2,4‐diones 12 , cyclize in excellent yields to 1‐aryl‐pyrazolo[4,3‐c]quinolin‐4‐ones (11). The cyclization conditions were investigated by differential scanning calorimetry (DSC).     

The formation of 3‐ferrocenylpyrazole‐4‐carboxylates and alkylhydrazine insertion products from α‐ferrocenylmethylidene‐β‐oxocarboxylates

The reactions of α‐ferrocenylmethylidene‐β‐oxocarboxylates ( 1 , 2 , 3a , and 3b ) with N‐methyl‐ and N‐(2‐hydroxyethyl)hydrazines ( 5a , 5b ) afford ethyl 1‐alkyl‐5‐aryl(methyl)‐3‐ferrocenylpyrazole‐4‐carboxylates ( 6a , 6b , 6c , 6d , 6e ) (～50%) and N‐alkylhydrazine insertion products, viz., ethyl (N′‐acyl‐N′‐alkylhydrazino)‐3‐ferrocenylpropanoates ( 7a , 7b , 7c , 7d , 7e ) (～20%) and 1‐acyl‐2‐(N′‐alkyl‐N′‐ethoxycarbonylhydrazino)‐2‐ferrocenylethanes ( 8a , 8b , 8c , 8d , 8e ) (～10%). The structures of the compounds obtained were established based on the spectroscopic data and X‐ray diffraction analysis (for pyrazoles 6a and 6b ). J. Heterocyclic Chem., (2011).     

Catalytic Enantioselective α‐Fluorination of 2‐Acyl Imidazoles via Iridium Complexes

The first highly enantioselective α‐fluorination of 2‐acyl imidazoles utilizing iridium catalysis has been accomplished. This transformation features mild conditions and a remarkably broad substrate scope, providing an efficient and highly enantioselective approach to obtain a wide range of fluorine‐containing 2‐acyl imidazoles which are found in a variety of bioactive compounds and prodrugs. A large scale synthesis has also been tested to demonstrate the potential utility of this fluorination method.     

Peculiar reaction of N2‐acyl derivatives of 2‐aryl‐5‐hydrazino‐1,3‐oxazole‐4‐carbonitriles with the lawesson reagent

Easily accessible N²‐acyl derivatives of 2‐aryl‐5‐hydrazino‐1,3‐oxazole‐4‐carbonitriles react peculiarly with the Lawesson reagent. In addition to thionation, the reaction involves a recyclization to afford new substituted 2‐(5‐amino‐1,3‐thiazol‐4‐yl)‐1,3,4‐thiadiazoles. Their structure is corroborated spectroscopically and by the X‐ray diffraction method. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:782–785, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20413     

Photochemistry of N‐(2‐Acylphenyl)‐2‐methylprop‐2‐enamides: Competition between Photocyclization and Long‐Range Hydrogen Abstraction

The photochemical reactions of various ‘N‐methacryloyl acylanilides’ (=N‐(acylphenyl)‐2‐methylprop‐2‐enamides) have been investigated. Under irradiation, the acyl‐substituted anilides 1a – 1c and 1o afforded exclusively the corresponding quinoline‐based cyclization products of type 2 (Table 1). In contrast, irradiation of the benzoyl (Bz)‐substituted anilides 1e – 1h afforded a mixture of the open‐chain amides 4e – 4h and the cyclization products 2e – 2h . Irradiation of the para‐acyl‐substituted anilides 6a – 6e and 6h afforded the corresponding quinoline‐based cyclization products of type 5 as the sole products (Table 2). The formation of the cyclization products 2a – 2c and 2o can be rationalized in terms of 6π‐electron cyclization, followed by thermal [1,5] acyl migration, and that of compounds 3p, 5a – 5e , and 5h can be explained by a 6π‐electron cyclization only. The formation of the open‐chain amides 4e – 4h probably follows a mechanism involving a 1,7‐diradical, C and a spirolactam of type D (Scheme). Long‐range ζ‐H abstraction by the excited carbonyl O‐atom of the benzoyl group on the aniline ring is expected to proceed via a nine‐membered cyclic transition state, as proposed on the basis of X‐ray crystallographic analyses (Fig. 2).     

The birch reduction of heterocyclic compounds V Birch reduction of 2‐ and 5‐acylfuran‐3‐carboxylic acids and reductive elimination of 2‐(arylmethoxymethyl)furan‐3‐carboxylic acids

The Birch reduction of 2‐ and 5‐acylfuran‐3‐carboxylic acid 1 and 4 gave 2‐acyl‐2,3‐dihydrofuran‐3‐carboxylic acid 2 and 5‐acyltetrahydrofuran‐3‐carboxylic acid 5 , respectively. Further examination of the reductive elimination was also studied on 2‐(arylmethoxymethyl)furan‐3‐carboxylic acids 7.     

A Facile and One‐pot Synthetic Route to Functionalized Ethyl 3‐(Alkanoyl)‐2‐(alkyl imino)‐2,3‐dihydrothiazole‐4‐carboxylate Derivatives under Mild,Solventand Catalyst‐free Conditions

A new one‐pot, four‐component synthetic rout is reported for the preparation of functionalized N‐acyl‐2alkylimino‐2,3‐dihydrothiazole derivatives from the reaction between acid chlorides, ammonium thiocyanate, primary alkylamines, and ethyl bromopyruvate under mild, solvent‐ and catalyst‐free conditions at room temperature. This completely green and efficient straight forward procedure led to the desired products in good to high yields without any need to catalyst or solvent assistance and no by product was observed in all the reactions