Reaction of methyl thiocarbamate with nonsubstituted malonyl dichloride. Effect of conditions on reaction direction

The reaction of methyl thiocarbamate with malonyl dichloride at low temperatures provides an N-substituted thiocarbamate, whereas prolonged boiling in high-boiling solvents gives rise to 4-hydroxy-2-(methylsulfanyl)-6H-1,3-oxazin-6-one that was also prepared by treatment of the N-substituted thiocarbamate with malonyl chloride in toluene and chlorobenzene.     

New syntheses of aliphatic isocyanates via cyannogen chloride

Alkylation of cyanogen chloride with alkyl chloride and ferric chloride gives an alkyl isocyanide dichloride-FeCl₃ complex 2. Such novel complexes react either with water to give alkylamines, or with alcohol or alcoholate to give the corresponding N-substituted carbamate, or are converted to alkyl isocyanates with various reagents. Cyanogen chloride, isopropyl chloride and ferric chloride give complex 2a which, with zinc oxide, gives isopropylisocyanate. Salts of caiboxylic acids also furnished the isocyanate in good yield. The t-butylisocyanide dichloride-FeCI₃ complex 2b does not react with zinc oxide but was transformed into f-butylisocyanate with trifluoroacetic acid or dimethyl sulphoxide.     

REACTION OF (2-BENZOTHIAZOLYL)-SULFENAMIDES WITH P-CONTAINING REAGENTS

Abstract

The title reaction was investigated to find that only substitution reaction on amino group occurred when (2-benzothiazolyl)sulfenamides 1 reacted with P(NR₂,)₃, whereas the treatment of 1 with (RO)P(NR₂,)₂, gave derivatives of phosphorodiarnidothioic acid together with 2-alkylthiobenzothiazole and its isomer in addition to substitution products, and no substitution products obtained when N-substituted analogues of 1 were treated similarly.     

Syntheses and properties of liquid crystalline N-substituted pyrroles and their polymers

Three liquid crystalline N-substituted pyrroles were synthesized from 6-(1-pyrrolyl)hexanol with phenolic derivatives having a mesogenic core of cyclohexylbenzene or biphenyl by Mitsunobu reaction. These pyrroles had two anodic peaks at 1.4 and 1.8 V (vs. SCE). The former was due to an oxidation of the pyrrole moiety and the latter was due to an oxidation of the mesogenic moiety. These pyrrole monomers were polymerized by electrochemical and chemical methods. The potentiostatic method and the chemical method using FeCl₃ gave a soluble and fusible polymer, respectively. A polymer having a mesogenic core of cyclohexyl benzene obtained by the chemical method and a polymer having a mesogenic core of biphenylketone obtained by the potentiostatic method had a liquid-crystalline phase. The phase was identified as smectic A by polarizing microscopy and XRD analysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2691–2698, 1998     

核苷类似物5-杂环取代或1,5-二杂环取代-1-α/β-D-5脱氧呋喃核糖的合成

核糖在酸的作用下于甲醇中闭环得到呋喃核糖甲苷,将其2,3-二羟基形成异亚丙基后,与对甲苯磺酰氯作用生成5-O-对甲苯磺酰基-2,3-O-异亚丙基-1-α/β-D-呋喃核糖甲苷,最后与取代哌嗪或吗啉反应,再在酸的作用下除去2,3-保护基,得到5-脱氧-5-杂环取代-1-α/β-D-呋喃核糖甲苷.它们的结构经~1H NMR和MS确证.     

Efficient synthesis of 1-R1-2-R-4,5-di(furan-2-yl)-1H-imidazoles and their luminescence properties

In this study, a series of 1-R₁-2-R-4,5-di(furan-2-yl)-1H-imidazole derivatives were synthesized in better yield 59.0%∼89.8% by the treatment of purified imidazole compounds with benzyl chloride or allyl chloride in the presence of sodium hydride, and were characterized by FT–IR, HRMS, ¹H NMR and ¹³C NMR spectroscopy. Furthermore, the luminescence properties of the synthesized products were investigated. It was found that N-substituted groups of imidazole have little influence on the absorption bands in a 0.1 N H₂SO₄ aqueous solution containing 0.5 mL of dissolved CH₃OH. However, the emission of some compounds in solution was sensitive to the polarity of the solvents.     

Effects of organic modifiers on the chiral recognition by different types of silica-immobilized bovine serum albumin

We prepared three columns containing bovine serum albumin immobilized on silica by different means and the effects of organic modifiers in the eluent on chiral separation were studied using N-substituted amino acids. Adsorption on silica, covalent immobilization to diol-silica with carbonyldiimidazole (CSP-II) and covalent immobilization to amino-silica with glutaraldehyde were studied. CSP-II had the highest stereoselectivity and was the most affected by organic modifiers in the eluent. The hydrophobicity of amino acid moiety affected the chiral recognition of N-benzoylamino acids and the aromaticity of the N-substituted group was important.     

Alkylation and Acylation of 1-(4-Phenylaminophenyl)dihydropyrimidine-2,4-(1H,3H)-diones

The C- and N-substituted derivatives of 1-(4-phenylaminophenyl)dihydropyrimidine-2,4-(1H,3H)-diones have been obtained by alkylation and acylation. The secondary amino group takes part in the acylation reaction, before the amide group of the heterocycle.     

Preparation of N-substituted amidines2

N-substituted amidines can be prepared in good yield by heating equimolecular quantities of aryl nitriles and primary amines with AlCl₃. Also when a nitrile is kept at room temperature in contact with hydrogen chloride gas in dry ether in the presence of arylamine, amidines may be formed in good yields.     

Synthesis, structure, and antibacterial activity of aminobenzofuroxan and aminobenzofurazan

The amination of 4,6-dichloro-5,7-dinitrobenzofuroxan and 4,6-dichloro-5,7-dinitrobenzofurazan with dibenzylamine followed the aromatic nucleophilic substitution pattern (S_NAr) and gave products of replacement of both chlorine atoms in the six-membered ring with elimination of hydrogen chloride. Regardless of the reactant ratio, 4,6-dichloro-5,7-dinitrobenzofuroxan was converted into 4,6-bis(dibenzylamino)-5,7-dinitrobenzofuroxan, whereas 4,6-dichloro-5,7-dinitrobenzofurazan under analogous conditions gave rise to unusual bisammonium derivative which lost proton from the amino group on C⁴ and benzyl group from the amino group on C⁶; as a result, the corresponding diamine with secondary and tertiary nitrogen atoms was obtained. The structure of the isolated compounds was determined by IR and NMR spectroscopy, elemental analysis, and X-ray analysis; their thermal stability was studied by simultaneous thermogravimetry and differential scanning calorimetry.     

Reactions of 4-chloro-3-formyl-coumarin with primary amines

The reaction of 4-chloro-3-formylcoumarin with primary amines in the presence of triethylamine was studied. The reaction with aliphatic and aromatic amines leads to N-substituted 4-amino-3-formylcoumarins, whereas hetarylamines react primarily with the formyl group to form a mixture of the Z-and E-isomers of N-substituted 3-aminomethylenechroman-2,4-diones. Replacement of the triethylamine by anhydrous sodium acetate in the reaction of chlorocoumarin with 2-aminopyridines leads to the formation of the condensed benzopyranopyridopyrimidine system as a result of nucleophilic attack of the amino group by the chlorine atom at position 4. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 660–668, May, 2006.     

Facile N-derivatization of alpha-amino esters and amides via benzotriazolylmethyl derivatives

Alpha-(N-substituted amino)esters were prepared in a two-step procedure from available unsubstituted alpha-amino esters. alpha-Amino esters are first converted into the corresponding N-benzotriazolylmethyl derivatives; in the second step, the benzotriazole group is substituted by various nucleophiles with or without the presence of a Lewis acid to give substituted alpha-amino esters in high overall yield under mild conditions with no signs of racemization. Boc-protected amino acids were converted into alpha-amino amides; subsequent deprotection allowed the conversion into N-substituted derivatives analogously to the alpha-amino esters, without racemization in high yields under mild conditions.     

Stereospecific synthesis of a dl-gala-aminoquercitol derivative

A new aminoquercitol derivative was synthesized starting from 1,4-cyclohexadiene. Photooxygenation of cyclohexa-1,4-diene afforded anti-2,3-dioxabicyclo[2.2.2]oct-7-en-5-yl hydroperoxide as the main product. The formed hydroperoxy endoperoxide was reduced with LiAlH₄ to produce anti-2,3-dioxabicyclo[2.2.2]oct-7-en-5-ol. Protection of alcohol with acetyl chloride followed by reduction of the endoperoxide with thiourea, and then palladium-catalyzed ionization/cyclization reaction gave an oxazolidinone derivative. Hydrolysis of the oxazolidinone ring and acetylation gave an amino compound. Oxidation of the double bond in the amino compound with OsO₄ followed by acetylation gave the amino tetraacetate and removal of the acetate groups furnished the desired aminoquercitol whose exact configuration was determined by X-ray diffraction analysis.     

Synthese von basisch substituierten 2-Methyl-2,3-dihydro-benzo[b]thiophenen

N-substituted {2-methyl-benzo[b]thienyl-(3)}-acetamides were oxidized to the corresponding 1,1-dioxides, catalytic hydrogenation of which gave N-substituted {2-methyl-2,3-dihydro-benzo[b]thienyl-(3)}-acetamide-S,S-dioxides. The latter were reduced by LiAlH₄ to give N-substituted 2-methyl-3-(β-amino-ethyl)-2,3-dihydro-benzo[b]thiophenes.     

Synthesis of piperidine derivatives fused to a tetrahydrofuran ring

Intramolecular nucleophilic opening of the oxirane ring in tert-butyl 6-(2-hydroxyethyl)-7-oxa-3-azabicyclo[4.1.0]heptane-3-carboxylate by the action of excess potassium hydroxide in 75% aqueous dimethyl sulfoxide at 110–120°C gave tert-butyl (3aR,7aS)-3a-hydroxyhexahydrofuro[2,3-c]pyridine-6(2H)-carboxylate whose treatment with POCl₃ resulted in elimination of water molecule and tert-butoxycarbonyl group with formation of 2,3,4,5,6,7-hexahydrofuro[2,3-c]pyridine hydrochloride. The latter reacted with electrophiles (acetic anhydride, methanesulfonyl chloride, and benzaldehyde in combination with sodium triacetoxyhydridoborate) in the presence of triethylamine, yielding the corresponding N-substituted 2,3,4,5,6,7-hexahydrofuro[ 2,3-c]pyridine derivatives.     

Unexpected opening of benzimidazole derivatives during 1,3-dipolar cycloaddition

Hydroxylamine hydrochloride adds via a Michael reaction on the acetonylidene moiety of (4Z)-(2-oxopropylidene)-1,2,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one, leading only to 2-[(5-methyl-isoxazol-3-yl)]methyl]benzimidazoles. This report describes the difference of reactivity of C-phenyl-N-phenyl formohydrazonoyl chloride with benzimidazole. For the N-substituted benzimidazole, an unexpected opening of the azole ring occurs, which was confirmed by single crystal X-ray diffraction analysis.     

氯乙烯/N-取代马来酰亚胺共聚竞聚率及共聚物组成

研究了氯乙烯(VC)与多种N-取代马来酰亚胺的溶液共聚合,求得各对单体的竞聚率.结果表明,各种马来酰亚胺的竞聚率都远高于VC的竞聚率,即N-取代马来酰亚胺单体的活性均比VC单体活性高.计算得到N-取代马来酰亚胺Q和e值.由于苯环的共轭效应,N-苯基及N-取代苯基马来酰亚胺具有较大的Q值.各对单体的e值差别较大,表明有形成交替共聚物的倾向.此外,还考察了聚合过程中共聚物组成的变化,用递推法预测了这类体系共聚物瞬时和累积组成随转化率的变化.     

Synthesis of pyrrolidine-substituted benzamides via iodocyclization of β-enaminoesters

Novel 2-, and N-substituted 5-methylene-pyrrolidine benzamides and 2-, 3-, and N-substituted 5-methylene-2-pyrroline benzamides were synthesized for the first time in a straightforward manner and in good yields via iodocyclization of γ- and α-alkenyl-β-enaminoesters, respectively. The key step in the process is the synthesis of the methylene-pyrrolidine iodide and methylene-2-pyrroline iodide intermediates. Functional group inter-conversion of these iodides to their amino analogs, and their subsequent coupling to benzoic acids via EDC, afforded the above pyrrolidine/2-pyrroline-substituted benzamides in yields of around 75%.     

Preparation and root growth-inhibitory activity of N-substituted 2-(2-chloroacetamido)-3-(furan-2-yl)propanamides

A series of N-substituted 2-(2-chloroacetamido)-3-(furan-2-yl)propanamides (16--18) was prepared through the reaction of chloroacetyl chloride with N-substituted 2-amino-3-(furan-2-yl)propanamides (15), which were obtained via condensation of 2-(tert-butoxycarbonylamido)-3-(furan-2-yl)propanoic acid (Boc-furylalanine) (8) with amines (9, 11, 13), followed by hydrolysis of the resultant N-substituted Boc-furylalanine acid amides (10, 12, 14) in the presence of HCl/dioxane. The biological activity of the prepared 16, 17 and 18 as root growth inhibitors was examined by germination assay using rape seed. At the concentration of 5.0 x10 (-5) M, the most active compound, 2-(2-chloroacetamido)-N-(2,6-diethylphenyl)-3-(furan-2-yl)propanamide (16 n), showed potent root growth-inhibitory activity of 76% towards rape seedlings.     

Synthesis of functional derivatives of aryl trichlorovinyl (trichloroallyl) ketones via consecutive transformations of the carbonyl group

An efficient procedure have been developed for the selective reduction of the carbonyl group in phenyl trichlorovinyl ketone and aryl trichloroallyl ketones by the action of NaBH₄ in propan-2-ol to obtain the corresponding alcohols. The hydroxy group in the latter was converted into amino by the Ritter reaction. Treatment of the alcohols and amines with 5-phenylisoxazole-3-carbonyl chloride and 4,5-dichloroisothiazole-3-carbonyl chloride gave the corresponding esters and amides, and condensation of the amines with aromatic aldehydes afforded Schiff bases.