192826-88-3

Upstream product

• 105-53-3 diethyl malonate 
• 15442-91-8 1,2,4,5-tetrabromomethylbenzene 

Downstream Products

• 261737-21-7 (CH₃C₆H₄SO₂OCH₂)2C(CH₂)2C₆H₂(CH₂)2C(CH₂OSO₂C₆H₄CH₃)2 

Relevant academic research and scientific papers

Diversity-oriented approach to novel spirocycles via 1,2,4,5-tetrakis(bromomethyl)benzene under operationally simple reaction conditions

Here, we have established a simple and an efficient methodology for the synthesis of spirocyclic α-amino acids as well as spirosulfones starting with readily available active methylene compounds (AMCs). The key di-bromo building blocks were assembled by reacting various active methylene compounds with 1,2,4,5-tetrakis(bromomethyl)benzene in one step. We have also expanded this strategy to generate a variety of bis-spirocycles by treating the di-bromo intermediates with different AMCs under operationally simple reaction conditions.

New spirans containing a 1,5-benzodithiepine system, derived from methylbenzenes. Conformational transmission

A synthesis of three new spirans, derived from methylbenzenes, containing the 1,5-benzodithiepine system is reported. X-ray structure proved the identity of model monospiran 9. In the solid and liquid state, the conformation of the seven-membered ring is chair, and the five-membered ring has the envelope conformation. The effect of conformational transmission in spirans 9 and 10 was observed. The synthesis of trispirans from hexamethylbenzene using the proposed scheme is also possible.

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).