The isomerization/chlorination of 0,0-dialkyl methylthiophosphonates with phosphorus oxychloride—a new convenient synthesis of S-alkyl methylthiophosphonic acid derivatives

A new method for the synthesis of S-alkyl methylthiophosphonic acid derivatives is reported. The chlorination of 0,0-dialkyl methylthiophosphonates 8 with phosphorus oxychloride proceeds with isomerization of the P=S to the P–S bond to give S-alkyl methylthiophosphonochloridates 9 , which react further with various nucleophiles in the presence of triethylamine to afford S-alkyl methylthiophosphonic acid derivatives 10 . Among them, several compounds 10 show excellent fungicidal or insecticidal activities. © 1995 John Wiley & Sons, Inc.     

A convenient synthesis of 2-hydrazinoethylphosphonic acid and derivatives

2-Hydrazinoethylphosphonic acid was prepared using a simple procedure involving Michael addition of hydrazine hydrate to diethyl ethenylphosphonate, followed by hydrolysis with hydrochloric acid. The product was converted into five- and six-membered heterocycles.     

A convenient synthesis of 2,2′-bipyridine derivatives

Picolinates 7 were prepared from the corresponding α-chloro-β-keto-esters 6. Esters 7 were converted into 2,2′-bipyridine derivatives 10 via triazines 9 using an aza Diels-Alder reaction.     

Condensation of α‐hydroxy ketones with phosphorus ylides: A convenient synthesis of linear heterocyclic formation

Reaction of α‐hydroxy ketones, furoin (1a) and/or benzoin (1b), with an appropriate phosphorus ylide (6a–d) provides access to new alkenes E‐8a–d, 15, 16 and/or furan derivatives 11a,b and 21. Furthermore, reaction of 1a,b with arylidenephosphorane 7 led to the formation of the respective dioxolo compound 22a,b. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 481–487, 1999     

A convenient synthesis of dihydrocoumarins from phenols and cinnamic acid derivatives

A facile procedure for synthesis of dihydrocoumarin derivatives was described. Although the yield of the products in the reaction of phenols with acrylates in trifluoroacetic acid in the presence of Pd(OAc)₂ giving coumarins was found to be very low, dihydrocoumarin derivatives were obtained in good to high yields in the absence of Pd(OAc)₂ when ethyl cinnamates bearing electron-donating groups were employed in this reaction.     

A convenient synthesis of pyridine and 2,2′-bipyridine derivatives

α-Chloro-α-acetoxy-β-keto-esters 9 were readily prepared from β-keto-esters 6 in good overall yields. These compounds reacted as α,β-diketo-ester equivalents 2 with amidrazones 1 yielding triazines 3, generally in good yields. Picolinates 10 provided an alternative source of α,β-diketo-ester equivalents 2 when treated with copper(II) acetate. A ‘one-pot’ reaction of the α,β-diketo-ester equivalents 2 with amidrazones 1 in the presence of 2,5-norbornadiene 5 in boiling ethanol yielded the pyridines 4 and 2,2′-bipyridines 4 (R¹=2-pyridyl) directly without the need to isolate the corresponding triazines 3. Triazine 3c reacted with the aza-dienophiles 13 and 17 affording the products 16 and 18, respectively, in good yields.     

A convenient, high-yield synthesis of 1-substituted uracil and thymine derivatives

Novel reagents for the synthesis of 1-substituted uracil and thymine derivatives have been developed. The aminolysis of 2- or 4-nitrophenyl 3-ethoxyacryloylcarbamate and 3-ethoxy-2-methylacryloylcarbamate with a variety of primary amino derivatives proceeded smoothly under very mild reaction conditions yielding almost quantitatively the 1,3-disubstituted urea derivatives. Their subsequent cyclization provided the 1-substituted uracil and thymine compounds, in almost quantitative yield.     

N,N,N'-不同基团三取代乙二胺衍生物的简便合成

以2-取代咪唑啉为起始原料,经过磺酰化反应,得到磺酰基咪唑啉2a-2e,然后进行甲基化反应得到1,2,3-三取代咪唑啉碘盐3a-3e。化合物3在室温下经过水解反应或还原反应,可得到两类不同基团N,N,N'-三取代乙二胺衍生物4或5。该反应具有条件温和、副产物少、产物得率高和后处理简单等优点,提供了一种有效的三步合成不同基团N,N,N'-三取代乙二胺衍生物的新方法。所合成产物通过NMR、IR和元素分析方法进行了结构确证。     

The reaction of amines with phthalimide derivatives a convenient synthesis of isoxazolidine

The reaction of tert-butylamine, isoxazolidine and hydrazine with N-[(3-chloropropyl)oxy]phthalimide is investigated. A convenient synthesis of oxazolidine is described.     

Electronic structure,novel synthesis,and O—H...O and C—H...O interactions in two 6‐oxopiperidine‐2‐carboxylic acid derivatives

Molecules of (S)‐6‐oxo‐1‐(thiophen‐2‐ylmethyl)piperidine‐2‐carboxylic acid, C₁₁H₁₃NO₃S, crystallize as single enantiomers in the space group P2₁ and the thiophene ring is disordered over two positions, while (S)‐6‐oxo‐1‐(thiophen‐3‐ylmethyl)piperidine‐2‐carboxylic acid, C₁₁H₁₃NO₃S, crystallizes as a single enantiomer in the space group P2₁2₁2₁. Their absolute configurations were confirmed by anomalous dispersion effects in diffraction measurements on the crystals. The molecules of each compound are linked by a combination of strong O—H...O hydrogen bonds and weak C—H...O interactions, resulting in two‐ and three‐dimensional networks, respectively, in the crystal structures.     

A convenient synthesis of (E)-conjugated polyene sulfonyl derivatives with excellent stereospecificity

A highly selective synthesis of conjugated polyene sulfonyl derivatives is described via the elimination of disulfonyl chloride with readily accessible raw material dihaloalkane. The protocol offers a convenient way to form sulfonamides, sulfonates and even sulfones. Furthermore, this method was manipulated under mild condition with simple operation in high yield to afford only trans products.     

A novel, convenient, and efficient procedure for the synthesis of spiroisoindoline-1,5′-oxazolidine derivatives

A novel, convenient, and practical one-pot procedure for the direct synthesis of spiroisoindoline-1,5′-oxazolidine derivatives is described via oxidative cleavage of 3a,8a-dihydroxyindeno[2,1-d]imidazole-2,8-diones with lead(IV) acetate at room temperature.     

The reaction of hypochlorous acid with olefins. A convenient synthesis of allylic chlorides

The reaction of HOCl with more highly substituted olefins in methylene chloride affords allylic chlorides in 60–80% isolated yields. The utility of the reaction is illustrated with the synthesis of Rose oxide and α-monoterpenes.     

A convenient synthesis of 1′-H-spiro-(indoline-3,4′-piperidine) and its derivatives

A simple synthetic route has been developed to prepare 1′-H-spiro(indoline-3,4′-piperidine) (1d). Dialkylation of 2-fluorophenylacetonitrile with N-(tert-butyloxycarbonyl)-bis(2-chloroethyl)amine (5) gave 6. Deprotection of Boc followed by cyclization resulted 1d in 67% overall yield. Selective Boc or Cbz protection of 1′-N gave 1a or 1b with 90 and 85% yield, respectively. Thus, in a five-step procedure, 1a and 1b were synthesized from commercially available reagents in over 50% overall yield. All 3 compounds (1a, 1b and 1d) can be utilized as templates to synthesize compounds for GPCR targets.     

The synthesis of heterocyclic derivatives of dibenzo[a,d]cycloheptene

The synthesis of 2-amino-7,8-dihydrobenzo[1,2]cyclohepta[3,4,5-de]quinazoline ( 10 ) and 6,7-dihydrobenzo[1,2]cyclohepta[3,4,5-cd]indazole ( 5 ) is described.     

Fatty acid hydrazides in heterocyclic synthesis: Synthesis of 1,2‐diazepine and pyridazine derivatives

1,2‐Diazepinone derivatives 6a–d, 8a,b, and 10a–c were synthesized from the reaction of olefines carrying EWG as ethoxymethylene malononitrile, ethoxymethylene cyanoacetate, and tetracyanoethylene with 1a–f respectively. Also, 5‐alkyl‐6‐oxotetrahydropyridazine‐4,4‐dicarboxylate derivatives 12a–c were afforded via the reaction of 1d–f with diethyl ethoxymethylene malonate. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:259–264, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20294     

A convenient synthesis of psoralen derivatives: Psoralen, 4-methyl-psoralen and 4-phenyl-psoralen

A convenient synthesis of psoralen derivatives, viz., 7H-furo [3.2-g] [1] benzopyran-7-one (psoralen), 5-methyl-7H-furo [3.2-g] [1] benzopyran-7-one(4-methyl-psoralen) and 5-phenyl-7H-furo [3.2-g] [1] benzopyran-7-one-(4-phenyl-psoralen) by blocking the 8-position of the starting compounds with iodine, subsequentClaisen migration followed by cyclisation is described

---

Ein Einfacher Syntheseweg zu Psoralen-Derivaten: Psoralen, 4-Methyl-psoralen und 4-Phenyl-Psoralen

Zusammenfassung Zur Synthese der Titelverbindungen wird die 8-Position des als Ausgangsmaterial dienenden 7-Hydroxy-benzopyranons mit Jod blockiert, dann erfolgt Allylierung und nach einerClaisen-Wanderung die Cyclisierung.

     

One-pot palladium-catalyzed highly chemo-, regio-, and stereoselective synthesis of trans-stilbene derivatives. A concise and convenient synthesis of resveratrol

A convenient, efficient and highly chemo-, regio-, and stereoselective one-flask synthetic method is reported for the construction of unsymmetrical (or symmetrical) trans-stilbene derivatives based on two sequential Heck-type reactions using tetraalkylammonium salt-based catalyst systems and vinyltrimethylsilane as double bond equivalents. Resveratrol has thus been concisely synthesized.     

Structure and isomerization of heterapentalene compounds containing hypervalent bonds with central nitrogen,phosphorus, or arsenic atom

The possibility for a specific type of isomerization (electromorphism) to occur in conjugated bicyclic organic compounds containing Group V elements was studied by the ab initio (RHF/6-31G**, MP2(full)/6-31G**), and DFT (B3LYP/6-31G**) methods. Compounds 2 (X = N, P, As) were found to exist in a monocyclic planar form with intramolecular donor-acceptor N...O coordination (X = N) and as aromatic heterapentalene structures with hypervalent O--X--O bonds (X = P, As). According to calculations, no isomerization of planar heteroaromatic structures into pyramidal ones occurs. The strength of the O--X--O hypervalent bond and the aromaticity of heterapentalene structures 2 with ten -electrons increase on going from X = N to X = P. Correct estimation of these effects requires the inclusion of electron correlation.