| Literature DB >> 35539652 |
Meenakshi Singh1, Abhijit Hazra1, Yogesh P Bharitkar1, Ritu Kalia1, Ashutosh Sahoo2, Sneha Saha1, V Ravichandiran1, Shekhar Ghosh2, Nirup B Mondal2.
Abstract
Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction using isatins/acenaphthoquinone and proline/thioproline as the reagents. The products were separated via extensive chromatography and characterized by 1D/2D NMR and HRMS analysis. This journal is © The Royal Society of Chemistry.Entities:
Year: 2018 PMID: 35539652 PMCID: PMC9080697 DOI: 10.1039/c8ra02725k
Source DB: PubMed Journal: RSC Adv ISSN: 2046-2069 Impact factor: 3.361
Scheme 1Synthesis of mixed bis-pyrrolizidino dispiro-oxindolo curcuminoids.
Yields of mixed bis-pyrrolizidino dispiro-oxindole 4(A-F)(a-d) derived from curcumin, isatins and proline
| Entry | R1 | R2 | R3 | R4 | R5 | R6 | Product | Yield |
|---|---|---|---|---|---|---|---|---|
| 1 | H | H | H | H | I | H | 4Aa | 20 |
| 2 | H | H | H | H | I | H | 4Ab | 23 |
| 3 | H | H | H | H | I | H | 4Ac | 21 |
| 4 | H | H | H | H | I | H | 4Ad | 24 |
| 5 | H | H | H | H | Me | Me | 4Ba | 19 |
| 6 | H | H | H | H | Me | Me | 4Bb | 22 |
| 7 | H | H | H | H | Me | Me | 4Bc | 21 |
| 8 | H | H | H | H | Me | Me | 4Bd | 23 |
| 9 | H | Cl | H | H | Me | H | 4Ca | 17 |
| 10 | H | Cl | H | H | Me | H | 4Cb | 20 |
| 11 | H | Cl | H | H | Me | H | 4Cc | 20 |
| 12 | H | Cl | H | H | Me | H | 4Cd | 23 |
| 13 | H | OMe | H | H | F | H | 4Da | 18 |
| 14 | H | OMe | H | H | F | H | 4Db | 22 |
| 15 | H | OMe | H | H | F | H | 4Dc | 21 |
| 16 | H | OMe | H | H | F | H | 4Dd | 24 |
| 17 | H | F | H | H | Me | Me | 4Ea | 18 |
| 18 | H | F | H | H | Me | Me | 4Eb | 22 |
| 19 | H | F | H | H | Me | Me | 4Ec | 21 |
| 20 | H | F | H | H | Me | Me | 4Ed | 23 |
| 21 | H | Me | Me | H | F | H | 4Fa | 17 |
| 22 | H | Me | Me | H | F | H | 4Fb | 20 |
| 23 | H | Me | Me | H | F | H | 4Fc | 20 |
| 24 | H | Me | Me | H | F | H | 4Fd | 22 |
Unless otherwise noted, the reaction was performed with 1.76 mmol of 3A-F(a) (±), isatins and proline in 50.0 mL of MeOH under reflux for 8 h.
Determined after isolation.
Fig. 1Possible mixed bis-pyrrolizidino dispiro-oxindolo curcuminoids via change in sequential addition of any two substituted isatins.
Scheme 2Synthesis of bis-thiopyrrolizidino dispiro-oxindolo curcuminoids.
Scheme 3Synthesis of mixed pyrrolizidino-thiopyrrolizidino dispiro-oxindolo curcuminoids.
Yields of mixed bis-thiopyrrolizidino dispiro-oxindole 6(A-E)(a-b) derived from curcumin, isatins, proline and thioproline
| Entry | R1 | R2 | R3 | R4 | R5 | R6 | Product | Yield |
|---|---|---|---|---|---|---|---|---|
| 1 | H | H | H | H | OMe | H | 6Aa | 30 |
| 2 | H | H | H | H | OMe | H | 6Ab | 35 |
| 3 | H | F | H | H | I | H | 6Ba | 32 |
| 4 | H | F | H | H | I | H | 6Bb | 37 |
| 5 | H | Cl | H | H | I | H | 6Ca | 31 |
| 6 | H | Cl | H | H | I | H | 6Cb | 35 |
| 7 | H | OMe | H | H | Me | Me | 6Da | 32 |
| 8 | H | OMe | H | H | Me | Me | 6Db | 36 |
| 9 | H | Me | H | H | Me | Me | 6Ea | 31 |
| 10 | H | Me | H | H | Me | Me | 6Eb | 36 |
Unless otherwise noted, the reaction was performed with 1.76 mmol of 3A-E(a) (±), isatins and thioproline in 50.0 mL of MeOH under reflux for 8 h.
Determined after isolation.
Fig. 2Important correlations of 6Aa and 6Ab [HMBC(), COSY()].
Scheme 4Synthesis of mixed bis-pyrrolizidino/-thiopyrrolizidino dispiro-oxindolo-acenapthylino curcuminoids.
Yields of mixed bis-pyrrolizidino/-thiopyrrolizidino dispiro-oxindolo-acenaphthylino curcuminoids 7A–D
| Entry | R1 | R2 | R3 | X | Product | Yield |
|---|---|---|---|---|---|---|
| 1 | H | H | H | –CH2 | 7A | 54 |
| 2 | H | I | H | –CH2 | 7B | 56 |
| 3 | H | H | H | –S | 7C | 50 |
| 4 | H | Me | H | –S | 7D | 49 |
Unless otherwise noted, the reaction was performed with 1.76 mmol of 3A-D(a) (±), isatins and proline in 50.0 mL of MeOH under reflux for 8 h.
Determined after isolation.
Fig. 3Important correlations of 7Bb and 7Db [HMBC(), COSY()].