ΜΕΛΕΤΗ ΑΝΤΙΔΡΑΣΕΩΝ 1,3-ΔΙΠΟΛΙΚΗΣ ΚΥΚΛΟΠΡΟΣΘΗΚΗΣ ΣΕ ΕΤΕΡΟΚΥΚΛΙΚΑ ΣΥΣΤΗΜΑΤΑ

THE MAIN PURPOSE OF THIS WORK IS TO STUDY THE 1,3-DIPOLAR CYCLOADDITION REACTIONS TO SUBSTITUTED EXOMETHYLENE-OXAZOLONES AND THIAZOLONES AND TO EXAMINE THESE REACTIONS AS A POSSIBLE SOURCE OF HETEROCYCLIC A-AMINOACID DERIVATIVES. (Z)- AND (E)-2- PHENYL-4-ARYLIDENE-5(4H)-OXAZOLONES REACT WITH NITRILIMINES AND (Z)-2-PHENYL-4-ARYLIDENE-5(4H)-THIAZOLONES WITH STABLE NITRILE OXIDES AND NITRILIMINES TO AFFORD SPIRO CYCLOADDUCTS, BY ADDITION OF THE DIPOLE ON THE EXOCYCLIC DOUBLE BOND. THE REACTIONS ARE STEREOSPECIFIC AND REGIOSELECTIVE, GIVING IN ALL CASES ONLY ONE REGIOISOMER, IN WHICH THE ANIONIC CENTER OF THE DIPOLE IS JOINED WITH THE TERTIARY CARBON ATOM OF OXAZOLONE-OR THIAZOLONE-RING. THE STRUCTURE OF THESE NEW COMPOUNDS WAS CONFIRMED BY SPECTROSCOPIC DATA AND BY CHEMICAL METHODS.THE OBSERVED REGIOCHEMISTRY IS ALSO RATIONALIZED BY FRONTIER MOLECULAR ORBITALCONSIDERATIONS OF THE REACTING SYSTEMS, USING EHMO-CALCULATIONS FOR THE MAGNITUDES OF OXAZOLONE ATOMIC ORBITAL COEFFICIENTS. ATTEMPTS TO CARRY OUT CYCLOADDITIONS REACTIONS OF THESE SYSTEMS WITH THE UNSTABLE BENZONITRILE OXIDE, NITRONES AND AZIDES WERE UNSUCCESSFUL. CYCLOADDITION REACTIONS WERE ALSO CARRIED OUT ON THE 2-PHENYL-4-ETHOXYMETHYLENE-5(4H)-OXAZOLONE. THE REGIOSELECTIVITY OF THESE REACTIONS IS DIFFERENT BECAUSE OF THE STRONG DIRECTIVE EFFECT OF THE ETHOXY MOIETY AND IN THE CYCLOADDITIONS THE ANIONIC CENTER OF THE DIPOLE IS JOINED WITH THE CARBON ATOM CARRYING THE ETHOXY-GROUP. THE CLEAVAGE OF THE ABOVE PREPARED SPIRO CYCLOADDUCTS WITH NUCLEOPHILES LEADS TO ISOXAZOLINE OR PYRAZOLINE A-AMINOACID DERIVATIVES. ESPECIALLY, CLEAVAGE REACTION WITH GLYCINE ETHYLESTER RESULTED DIPEPTIDES CONTAINING HETEROCYCLIC RING. IN A COMPARISON WITH THE ABOVE STUDIED DIPOLAROPHILES, CYCLOADDITIONS OF METHYL-(Z)- AND (E)-A- BENZAMIDO- CINNAMATES WITH NITRILOXIDES AND NITRILIMINES WERE ALSO EXAMINED. THESE REACTIONS SHOW THESAME REGIOSELECTIVELY AND GIVE THE SAME PRODUCTS OBTAINED FROM THE METHANOLYSIS OF THE (Z)- AND (E)-SPIRO CYCLOADDUCTS RESPECTIVELY, CONFIRMING THAT NUCLEOPHILIC CLEAVAGE OF OXAZOLONE-RING IS STEREOSPECIFIC.

Grantor dc:publisher

Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)

Year dc:date

1990

Author dc:creator

• Θεσσαλονικέως, Ελισάβετ

• 1,3-DIPOLAR CYCLOADDITION REACTIONS
• 2-PHENYL-4-ARYLIDENE-5(4H)-OXAZOLONES
• 2-PHENYL-4-ARYLIDENE-5(4H)-THIAZOLONES
• 2-PHENYL-4-ETHOXYMETHYLENE-5(4H)-OXAZOLONE
• 2-ΦΑΙΝΥΛΟ-4-ΑΙΘΟΞΥΜΕΘΥΛΕΝΟ-5(4Η)-ΟΞΑΖΟΛΟΝΗ
• 2-ΦΑΙΝΥΛΟ-4-ΑΡΥΛΙΔΕΝΟ-5(4Η)-ΘΕΙΑΖΟΛΟΝΕΣ
• 2-ΦΑΙΝΥΛΟ-4-ΑΡΥΛΙΔΕΝΟ-5(4Η)-ΟΞΑΖΟΛΟΝΕΣ
• ISOXAZOLINE A-AMINOACID OR DIPEPTIDE DERIVATIVE
• METHYL A-BENZAMIDO-CINNAMATE
• Nitrile oxides
• NITRILIMINES
• PYRAZOLINE A-AMINOACID OR DIPEPTIDE DERIVATIVES
• Α-ΒΕΝΖΑΜΙΔΟ-ΚΙΝΝΑΜΩΝΙΚΟΣ ΜΕΘΥΛΕΣΤΕΡΑΣ
• Αντιδράσεις 1,3 διπολικής κυκλοπροσθήκης
• ΙΣΟΞΑΖΟΛΙΝΙΚΑ ΠΑΡΑΓΩΓΑ Α-ΑΜΙΝΟΞΕΩΝ Η ΔΙΠΕΠΤΙΔΙΩ
• ΝΙΤΡΙΛΙΜΙΝΕΣ
• Νιτριλοξείδια
• ΠΥΡΑΖΟΛΙΝΙΚΑ ΠΑΡΑΓΩΓΑ Α-ΑΜΙΝΟΞΕΩΝ Η ΔΙΠΕΠΤΙΔΙΩΝ
• Φυσικές Επιστήμες
• Natural Sciences
• Χημεία
• Chemical Sciences

Language dc:language

gre

Identifier

10.12681/eadd/1347

OAI identifier oai:identifier

oai:10442/1347