100-07-2Relevant articles and documents
Mild hydrolysis or alcoholysis of amides. Ti(IV) catalyzed conversion of primary carboxamides to carboxylic acids or esters
Fisher,Caroon,Stabler,Lundberg,Zaidi,Sorensen,Sparacino,Muchowski
, p. 142 - 145 (1994)
Reaction of primary amides (e.g., 1a or 6-13) or O-methylhydroxamates (1b and 1c) with a catalytic amount of TiCI4 and one equivalent of aqueous HCI converts these compounds in good yields to carboxylic esters (when an alcohol is used as solvent) or to carboxylic acids (when 9:1 dioxane:H2O is used as solvent). These conversions are chemoselective for primary amides: mono- and dialkyl amides are not affected by the reaction conditions. The hydrolysis conditions described do not compromise the stereochemical integrity of an adjacent chiral center. This is exemplified by the hydrolysis of naproxen amide (34) to naproxen (33) without detectable racemization as determined by chiral HPLC.
Dependence of Liquid-Crystal Behavior of a Substance on Molecular Structure
Makwana,Doshi
, p. 93 - 101 (2015)
A novel azoester homologous series of liquid crystals (LCs) consisting of 12 members has been synthesized and evaluated. All members of the series exhibit the nematic mesophase enantiotropically without the exhibition of a smectic mesophase. The textures of the nematic phase are threaded or Schlieren in type. The transition curves in the phase diagram behave in a normal manner. The N-I transition curves exhibit an odd-even effect. The analytical and spectral data support the molecular structures of the homologs. The transition temperatures and mesophase morphology were determined by an optical polarizing microscope equipped with a heating stage. The azoester compounds consist of three phenyl rings with a meta substituted -Cl group at the middle phenyl ring and -OR and -OCH3 as terminal end groups. The average nematic thermal stability is 195°C and the nematogenic mesophase length ranges from 9°C to 186°C. The LC behaviors of the series are compared with a structurally similar series. The novel series is entirely nematogenic and of a high melting point type.
Mesomorphism dependence on positional substitution of same polar group on same phenyl ring in isomeric homologous series
Prajapati,Doshi
, p. 62 - 71 (2015)
Novel homologous series 4-(4′-n-alkoxy benzoyloxy) napthyl azo 2″ - nitro benzenes, consisted of eleven members of a series. All the eleven members (methoxy to tetradecyloxy) homologs are only enantiotropically nematogenic without exhibition of any smectogenic character. Transition temperatures and the textures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Analytical and spectral data supported the molecular structure of homologs. Transition curves viz., solid-nematic and nematic-isotropic showing phase behavior of the mesophase in a phase diagram behave in normal manner. Odd-even effect and alternation of transition temperatures are exhibited by N-I transition curve. N-I thermal stability is 129.7°C and Nematic mesophase vary from 12 to 64°C. Thus, novel series is entirely nematogenic and middle ordered melting type. Mesomorphic behavior of a novel series are compared with the structurally similar homologous series.
Synthesis and study of novel liquid crystalline homologous series: 4-(4′- n -alkoxy benzoyloxy)-3-methoxy phenyl azo-3″, 4″ dichlorobenzenes
Chauhan,Doshi, Ankita A.,Doshi
, p. 84 - 91 (2013)
The synthesis and mesomorphic properties of a new homologous series of azomesogens, 4-(4′-n-alkoxy benzoyloxy)-3-methoxy phenyl azo-3″,4″ dichlorobenzene is detailed. The first four members of the series are nonmesomorphic, and the other eight members are smectogenic in character. The smectic mesophase, which is exhibited montropically, commences from the pentyl to the hexadecyl derivatives. The usual odd-even effect is observed in the isotropic-smectic transition curve. The isotropic-smectic transition curve behaves in a normal manner. The smectic mesophase shows a focal conic fan shaped texture of the smectic A type. An important feature of the series is the absence of the nematic property. The thermal stability and mesomorphic characteristic are compared with two structurally similar homologous series.
Facile synthesis of acacetin-7-O-β-d-galactopyranoside
Zacharia, James T.,Hayashi, Masahiko
, p. 91 - 94 (2012)
Acacetin-7-O-β-d-galactopyranoside (1), a natural flavonoid isolated from flower heads of Chrysanthemum morifolium, has been reported to inhibit the replication of HIV in H9 cells. We achieved the total synthesis of compound 1 by employing a one-pot synthesis of the aglycon. The key reactions in this approach include the modified Baker-Venkataraman reaction and regio- and stereoselective O-glycosylations.
1-Phenacylmethyl-2-(acylaminothiocarbonylamino)pyridinium bromides as protectors of steel acid corrosion
Yurchenko,Pogrebova,Pilipenko
, p. 675 - 677 (2007)
Inhibiting effect of 1-phenacylmethylpyridinium bromides containing acylthiourea substituents in the pyridine ring on corrosion of mild steel in sulfuric acid (3 M) was studied.
Mesomorphism dependence on molecular flexibility
Travadi,Vadodaria,Ladva,Doshi
, p. 69 - 78 (2016)
A novel ester homologous series of liquid crystals with a highly polar laterally substituted –OCH3 group is synthesized and studied with a view to understanding and establishing the effects of molecular structure involving lateral substitution on liquid crystal behavior. The novel series RO·C6H4·COO·C6H3·OCH3(ortho)CH=CH·COO·C2H5 consists of 12 homologs of which C7, C8, C10 are nematogenic and C12, C14, C16 homologs are smectogenic. The rest of the homologs are nonliquid crystals. The textures of nematic phase are threaded and the smectic phase is of the type A or C. Transition temperatures and the textures of mesophases were determined by an optical polarizing microscope equipped with a heating stage. Analytical and spectral data support the molecular structures. The N-I and Sm-I transition curves behave in normal manner without exhibition of an odd-even effect. Average thermal stability for smectic and nematic are 127.3°C and 129°C, respectively. The total mesophase length ranges from 17°C to 57°C and series is of a middle ordered melting type with transition temperatures varying between 82°C and 148°C. The liquid crystal properties of present novel series are compared with, structurally similar known homologous series.
An unexpected and green synthetic protocol for ethyl 1-aroyl/aroylmethyl-5- methyl-3-methylthiopyrazole-4-carboxylates: High regioselectivity in alkylation and acylation reactions between n-1 and n-2 of a pyrazole ring
Wen, Li-Rong,Wang, Shu-Wen,Li, Ming,Qi, Wen-Ying,Zhang, Xiu-Li,Yang, Hua-Zheng
, p. 1021 - 1028 (2005)
Two series, totaling twelve, of new compounds, ethyl 1-aroyl/(aroylmethyl)- 5-methyl-3-methylthiopyrazole-4-carboxylates (5/6), have been synthesized via highly regioselectively acylation and alkylation reactions of ethyl 3-methyl-5-methylthio-1H-pyrazole
The synthesis and mesomorphic properties of a novel homologous series: α-4-[4′-n-alkoxy benzoyloxy] benzoyl-β-2″-nitro phenyl ethylenes
Chauhan,Doshi
, p. 92 - 100 (2013)
The synthesis and mesomorphic properties of novel homologous series are reported. All 11 members of the series, except the methoxy and ethoxy derivatives, are enantiotropically mesogenic. The propoxy to tetradecyloxy homologues exhibits smectognic amd nematogenic behavior, while the hexadecyloxy homologue shows only nematogenic behavior. An odd-even effect is observed for the smectic-nematic and the nematic-isotropic transition curve in the phase diagram. Analytical data support the structure of molecules. The textures of the nematic mesophase are threaded or Schlieren, and that of smectic mesophase are of type-A. The transition temperatures of homologues and other mesomorphic properties are determined using optical polarizing microscopy. The smectic and nematic thermal stabilities are 138.0°C and 163.8°C respectively. The novel series is predominantly nematogenic and partly smectogenic with middle-ordered melting type. The nematic and smectic phase ranges vary between 16°C and 38°C and 6°C and 22°C respectively. The mesogenic properties of the novel series are compared with other structurally similar homologous series.
A practical chlorination of tert-butyl esters with PCl3 generating acid chlorides
Wu, Xiaofang,Zhou, Lei,Yang, Ruoqi,Guo, Fengzhe,Tang, Zi-Long,Xiao, Jing
, p. 301 - 304 (2020)
For the first time, using PCl3, a range of tert-butyl esters is chlorinated successfully, allowing access of both aromatic acid chlorides and aliphatic acid chlorides in good yields. The method features simple reaction conditions and wide substrate scope. Various tert-butyl esters including aryl esters, alkenyl esters, and alkyl esters were tolerated well in the reaction. A plausible mechanism is proposed.
