Synthesis of Guanidines from Amines and Carbodiimides Catalyzed by Mono-lndenyI-Ligated Rare Earth Metal Bis（silylamide） Complexes

Nucleophilic addition of primary aromatic amines to carbodiimides in the presence of catalytic amount of the mono-indenyl-ligated rare earth metal bis（silylamide） complexes （C9H6CMe2CHzCsH4N-a）Ln[N（SiHMe2）2]2 at room temperature afforded efficiently a series of guanidines with a wide spectrum of substituents on the nitrogen atoms.

Efficient Synthesis of 3,5,6,7-Tetrahydro-4H-cyclopenta [4,5] thieno [2,3-d] Pyrimidin-4-ones

The title compounds 3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-ones（6） were synthesized by base catalytic reactions of secondary amines with carbodiimides 4, which were obtained from the aza-Wittig reaction of iminophosphoranes（3） with aromatic isocyanates.

Efficient synthesis of 4(3H)-quinazolinones using a soluble polymeric support

4（3H）-Quinazolinones have been synthesized from poly（ethylene glycol） （PEG） supported aza-Wittig reaction. 2-Dialkylamino- 4（3H）-quinazolinones 6 were synthesized efficiently by reaction of secondary amine with PEG-supported carbodiimides 4, which were obtained from aza-Wittig reaction of PEG-supported iminophosphoranes 3 with isocyanates.

A Selective Synthesis of 2-Alkylamino-5, 6, 7, 8-tetrahydro-benzothieno[2, 3-d]pyrimidin-4(3H)-ones

Alkylamino-5, 6, 7, 8-tetrahydrobenzothieno [2, 3-d] pyrimidin-4(3H)-ones 7 weresynthesized by a new selective synthetic method, which includes aza-Wittig reaction of imino-phosphorane 4 with aromatic isocynate to give carbodiimide 5 and subsequent reaction of 5 withvarious aliphatic primary amine in the presence of EtO-Na+.

Efficient synthesis of 5,6-dihydrothieno[3′,2′:4,5]-thieno[2,3-d]pyrimidin-4(3H)-ones via an iminophosphorane

5,6-Dihydrothieno[3＇,2＇：4,5]thieno[2,3-d]pyrimidin-4（3H）-ones 6 were synthesized in yields of 71-87% by a consecutive method, which includes aza-Wittig reaction of iminophosphorane 3 with aromatic isocynate to give carbodiimide 4 and subsequent reaction of 4 with various amines, phenols or alcohols in the presence of catalytic amount of sodium ethoxide or solid potassium carbonate. 2009 Ming Wu Ding. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Formation and Crystal Structure of 1-(N-tert-butyloxycarbonyl-L-prolyl)-1,3-dicyclohexylurea

The title compound 1-（N-tert-butyloxycarbonyl-L-prolyl）-1,3-dicyclohexylurea formed in the coupling reaction of N-Boc-L-proline and n-butyl amine activated by DCC as an unexpected product was characterized through IR,1H NMR,13C NMR and HRMS spectra as well as single-crystal X-ray diffraction analysis.The crystal（C23H39N3O4,Mr = 421.57） belongs to the orthorhombic system,space group P212121,a = 10.8990（5）,b = 12.2153（6）,c = 18.8102（9） ,V = 2504.3（2） 3,Z = 4,Dc = 1.118 g/cm3,λ（MoKα） = 0.71073 ,μ = 0.076 mm-1,F（000） = 920,the final R = 0.0572 and wR = 0.1521 for 3564 observed reflections with I 〉 2σ（I）.An intramolecular hydrogen bond N（3）-H…O（2） is observed.

Efficient hydrocarboxylation of alkynes based on carbodiimide‐regulated in situ CO generation from HCOOH:An alternative indirect utilization of CO_(2)

The role of carbodiimide as dehydrant in the chemo‐,regio‐and stereoselective Pd(Ⅱ/0)‐catalyzed hydrocarboxylation of various alkynes with HCOOH releasing CO in situ is reported for the first time to obtainα,β‐unsaturated carboxylic acids.Both symmetrical and unsymmetrical monoalkynes show good reactivity.Importantly,2,2’‐(1,4‐phenylene)diacrylic acid can also be synthesized in high yield through the dihydrocarboxylation of 1,4‐diethynylbenzene.Besides,an excellent result in gram scale experiment and TON up to 900 can be obtained,displaying the efficiency of this protocol.Notably,regulating the types and concentrations of dehydrant can control the CO generation,avoiding directly operating toxic CO and circumventing sensitivity issue to the CO amount.On the basis of the attractive features of formic acid including easy preparation through CO_(2) hydrogenation and efficient liberation of CO,this protocol using formic acid as bridging reagent between CO_(2) and CO can be perceived as an indirect utilization of CO_(2),offering an alternative method for preparing acrylic acid analogues.

The preservation effects of chitosan copolymers(gallic acid and protocatechuic acid)on sea bass(Lateolabrax japonicus)fillets

This study was aimed at preparing chitosan(CS)-phenolic acids copolymers to obtain better preservation effect in marine products.In this work,CS was grafted onto phenolic acids such as gallic acid(GA)and protocatechuic acid(PA)by a carbodiimide coupling method.The copolymers(CS-grafted-GA(CS-g-GA)and CS-grafted-PA(CS-g-PA))were further confirmed through physicochemical properties including ultraviolet-visible(UV-Vis)spectrophotography,fourier transform infrared(FTIR)spectrometry,differential scanning calorimetry(DSC)thermogram,rheological behaviour,scanning electron microscope(SEM)and antioxidant activity analysis.Subsequently,the effects of copolymers on preservation of refrigerated sea bass(Lateolabrax japonicus)fillets were investigated.The results showed that the CS-g-GA(110.82 mg GA/g)exhibited higher grafting rate than CS-g-PA(62.63 mg PA/g).According to the assessment of UV-Vis and FTIR spectrometry,both the GA and PA were grafted onto CS successfully.SEM analysis demonstrated that the microstructure of copolymers became irregular.Meanwhile,both the CS-g-GA and CS-g-PA copolymers displayed superior thermal stability,rheological properties and antioxidant capacity than the pure CS.Furthermore,the copolymers also revealed a significantly stronger preservation effect on sea bass fillets including inhibiting microbial growth and delaying the deterioration of color,texture and sensory quality.Therefore,CS-g-GA and CS-g-PA could be used as promising preservatives for seafood.

An efficient route for synthesis of 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4(3H)-one

The carbodiimide 2,obtained from the aza-Wittig reactions of iminophosphorane 1 with alkyl isocyanates,reacted with primary amino to give 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4（3H）-ones 4 and 5.The formation mechanism of the title compounds has been investigated.

Synthesis of new 1,2,4-oxadiazolidin-5-ylthiophenes and thienopyrimidine derivatives by aza-Wittig reaction using a thienyl carbodiimide

Azidation of aminothiophene derivative 1 afforded the corresponding azido derivative 2.The latter reacted with triphenylphosphine to afford iminophosphorane derivatives 3.Reacting 3 with phenylisocyanate gave the highly reactive carbodiimide intermediate 4,which was reacted with different nitrones to afford new l,2,4-oxadiazolidin-5-ylidene-aminothiophenes 5a-c. Treatment of 4 with absolute EtOH at room temperature gave methyleneamino-5-（methylthio）thiophene 7,（methylthio）-3-（3- phenylureidothiophene）-2-carboxylate 8 or thienopyrimidine 9 and 10 at refluxing temperature.Finally reaction of carbodiimide intermediate 4 with different secondary amines gave the new thienopyrimidines 11a-c.

Potential of capillary electrophoresis mass spectrometry for the characterization and monitoring of amine-derivatized naphthenic acids from oil sands process-affected water

Capillary electrophoresis coupled to mass spectrometry（CE–MS） was used for the analysis of naphthenic acid fraction compounds（NAFCs） of oil sands process-affected water（OSPW）. A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE–MS in less than 15 min. Time of flight MS analysis（TOFMS）, optimized for high molecular weight ions, showed NAFCs between 250 and 800 m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs（between 100 and 450 m/z） are visible under our experimental conditions. Derivatization of NAFCs consisted of two-step amidation reactions mediated by 1-ethyl-3-（3-dimethylaminopropyl）carbodiimide（EDC）, or mediated by a mixture of EDC and N-hydroxysuccinimide, in dimethyl sulfoxide, dichloromethane or ethyl acetate. The optimum background electrolyte composition was determined to be 30%（V/V） methanol in water and 2%（V/V） formic acid. NAFCs extracted from OSPW in the Athabasca oil sands region were used to demonstrate the feasibility of CE–MS for the analysis of NAFCs in environmental samples, showing that the labeled naphthenic acids are in the mass range of 350 to 1500 m/z.

New efficient synthesis of 2,5,6-trisubstituted oxazolo[5,4-d]pyrimidi-7(6H)-ones via an oxazolyliminophosphorane

A new efficient synthesis of 2,5,6-trisubstituted oxazolo（5,4-d]pyrimidi-7（6H）-ones by consecutive azaWittig reaction was developed.The sequential three-component reaction of oxazolyliminophosphorane4,isocyanates and amines produced 2,5,6-trisubstituted oxazolo[5,4-d]pyrimidi-7（6H）-ones 7 in good overall yields in the presence of catalytic amount of EtONa.

Neodymium Complex Obtained from Reductive-coupling of Carbodiimide： Synthesis and Structure of [（Cp＇＇）2Nd（NR）2C- C（NR）2Nd（Cp＇＇）2]

A bimetallic oxalamidino complex of neodymium [（Cp＇＇）2Nd（NR）2C-C（NR＇）2Nd（Cp＇＇）2][Cp＇＇= η5-C5H3-1,3-（SiMe3）2, R=C6H11]（2） was obtained via reaction between Ndl2 and carbodiimide[RN：C：NR] （R=C6H11）（molar ratio 1：1） in tetrahydrofuran（THF） solution, followed by the addition of [KCp＇＇（THF）]（1）（molar ratio 1：2） at a low temperature through a reductive-coupling reaction with carbodiimide. The structure of the intermediate product was confirmed by means of elemental analysis, ^1H NMR and ^13C NMR. Characterization of the product by single crystal X-ray diffraction confirmed the diamidinate type of structure.

An Efficient Synthesis of 3-Alkyl-2-alkyliminooxazolidin-4-one via a Domino Reaction

3-Alkyl-2-alkyliminooxazolidin-4-ones were prepared from a copper-catalyzed domino intermolecular nucleophilic addition of a-hydroxy-（or mecapto） carboxylic acid ester to carbodiimide and a followed nucleophilic substitution of the formed amino group to carboxylic acid ester. The reactions could be performed under convenient conditions and good yields were achieved in most cases.