69403-16-3

Upstream product

• 91-13-4 α,α'-dibromo-o-xylene 
• 105-53-3 diethyl malonate 
• 612-12-4 o-Xylylene dichloride 
• 50423-49-9 1,2-bis(iodomethyl)benzene 

Downstream Products

• 55444-18-3 3-[2-(2-ethoxycarbonyl-ethyl)-phenyl]-propionic acid ethyl ester 
• 37949-03-4 5,6,8,9-tetrahydrobenzo[7]annulen-7-one 
• 127183-55-5 o-xylylenedi-malonic acid 
• 871876-94-7 3,3'-(1,2-phenylene)dipropionic acid 
• 129075-84-9 3-(2-ethylphenyl)propanoic acid 

Relevant academic research and scientific papers

EMM-31 MATERIALS AND PROCESSES AND USES THEREOF

The disclosure is related to EMM-31 materials, processes, and uses of the same as well as reagents used in the preparation of the EMM-31 materials, process and intermediates for preparing these reagents.

Tetrahydro-as-indacenyl catalyst composition, catalyst system, and processes for use thereof

This invention relates to a compound represented by the formula: TyLAMXn-2 wherein: A is a substituted or unsubstituted tetrahydro-as-indacenyl group bonded to M; L is substituted or unsubstituted monocyclic or polycyclic arenyl ligand or monocyclic or polycyclic heteroarenyl ligand bonded to M; M is a group 3, 4, 5, or 6 transition metal (preferably group 4); T is a bridging group bonded to L and A; y is 0 or 1, indicating the absence or presence of T; X is a leaving group, typically a univalent anionic ligand, or two Xs are joined and bound to the metal atom to form a metallocycle ring, or two Xs are joined to form a chelating ligand, a diene ligand, or an alkylidene; n is the oxidation state of M and is 3, 4, 5, or 6.

Palladium-catalyzed distannylation of ortho-quinodimethanes

An exo-diene moiety of various ortho-quinodimethanes, regardless of its transient character, was inserted into a Sn-Sn σ-bond of hexabutyldistannane in the presence of a palladium catalyst, giving α,α′-bis(tributylstannyl)-o-xylenes straightforwardly.

Efficient synthesis and theoretical study of siloxy-benzocyclooctenes: 7,8,-Bis-trimethylsilanyloxy-5,6,9,10-tetrahydro-benzocyclooctene and 6,9-dimethyl-7,8-bis-trimethylsilanyloxy-5,6,9,10-tetrahydro-benzocyclooctene -6,9-dicarboxylic acid diethyl ester

2-[2-(2,2-Bis-ethoxycarbonyl-ethyl)-benzyl]malonic acid diethyl ester 2, 3-[2-(2-ethoxycarbonyl-ethyl)-phenyl]-propionic acid ethyl ester 3, 2-[2-(2,2-bis-ethoxycarbonyl-propyl)-benzyl]-2-methyl-malonic acid diethyl ester 4, 7,8-bis-trimethylsilanyloxy-5,6,9,10-tetrahydro-benzocyclooctene 5, and 6,9-dimethyl-7,8-bis-trimethylsilanyloxy-5,6,9,10-tetrahydro-benzocyclooctene -6,9-dicarboxylic acid diethyl ester 6 have been synthesised for study of their spectroscopic and structural features. The synthetic method involved is monoalkylation of malonic acid diethyl ester and 2-methyl-malonic acid diethyl ester with 1,2-bis-bromomethyl-benzene in DMSO, and yields esters 2 and 4, respectively. The decarboxylation of 2 by DMSO/LiCl in the presence of a very small amount of water yields diester 3. Compounds 3 and 4 undergo acyloin condensation to give siloxy-benzocyclooctenes 5 and 6, respectively. The calculated structures and parameters of bis-siloxy-benzocyclooctene 6 show the reason why cyclization of 4 was independent of the quantity of reagents used. (C) 2000 Elsevier Science Ltd.

Mono- vs. dialkylation of carbanions. Effects of absolute and relative acidity of the conjugate carbon acids in selectivity control

The title problem was investigated in the reaction of the dibromide 1 with carbanions 2a-2g covering a range greater than 15 pK units in DMSO. It was found that the bis(monoalkylated) product 3 arises exclusively or predominantly from the carbanions 2d-2g derived from the less acidic carbon acids 7d-7g whereas the cyclic product of dialkylation 4 prevails in the reaction of the carbanions 2a-2c derived from the more acidic carbon acids 7a-7c. The alkylation selectivity thus depends critically on the absolute acidity of the carbon acid participating in the reaction. Rationale for this novel, and on basis of earlier studies unexpected finding is provided in terms of eqs. (1)-(4).

Solvent and leaving g roup effects on the mono- vs. Dialkylation of alkali salts of diethyl malonate with 1,2-bis-, 1,2,4,5-tetrakis- and 1,2,3,4,5,6-hexakis-(Halomethyl)benzenes. A new insight into selectivity control of malonester synthesis.

Contrary to tile widely held opinion that protic ('acidic') solvents favor monoalkylation whereas aprotic ('inert') solvents support dialkylation of diethyl malonate carbanion exactly opposite results have been obtained in the reaction of the dibromide 7, tetrabromide 4 and hexabromide 1 in ethanol and dimethyl sulfoxide, the former solvent preferring strongly dialkylation (cyclization) and the latter monoalkylation. Investigation in a broader spectrum of solvents demonstrated that hydrogen bonding as well as ion-pairing may play an important role in the selectivity control, both strongly supporting dialkylation. When a separation of ion-pairs is induced with 18-crown-6, monoalkylation prevails in the reaction. The solvent and die leaving group employed have been found to participate in the selectivity control. In DMSO, propensity to dialkylation increases strongly in die order I Br CI, again in discord with earlier predictions. Rationale for the novel findings is provided on the basis of kinetic analysis of the overall reaction and is expressed by the limiting equations (5) and (7).