Joel Jones Junior

Desenvolvimento sustentável e química verde

The world is in a process of awakening with respect to the environment. Our society has started to recognize that the environment is one of our largest resources and has begun legally enforce its protection. In Brazil, the environmental law is constitutionally guaranteed. International treaties have been signed, amongst them the Agenda 21 which is a commitment to sustainable development. Green Chemistry is a strategy that helps make this commitment. The literature presents many examples of studies of the application of Green Chemistry philosophy. In this paper we will present some points that we believe to be important and promising.

Michael Additions of Thiocompounds to AB -Unsaturated Carbonyl Compounds in Aqueous Media: Stereoselectivity with Unambiguous Characterization by NMR

The reactions of crotonaldehyde (8) with thiophenol (2) and benzalacetone (10) with ethane-1,2-dithiol (11) yield Michael addition products. The reactions of thiophenol (2) with (R)-carvone (13) and (S)-perillaldehyde (15) lead to (2S,3R,5S)-5-isopropenyl-2-methyl-3-(phenylthio)cyclohexanone (14) and (1R,2R,4S)-4-isopropenyl-2-(phenylthio)cyclohexanecarbaldehyde (16), respectively. An unambiguous elucidation of the stereochemistry of 14 and 16 by NMR is also presented.

Methods of cyclization of some δ-diketones

Abstract Three methods of cyclizing δ-diketones where the β- and γ-carbons form part of a ring system were studied: 1) strong base in protic media; 2) strong aqueous acid biphasic with apolar solvent; 3) alumina with saturated hydrocarbons. General limits were established for each method and a system validated for preparative scale cyclization without isomerization of an external double bond.