Abstract
A modified and efficient Knoevenagel condensation procedure was developed to synthesize the title compounds using β-alanine and acetic acid as catalysts, showing good to excellent yields. We used lawsone with suitable aliphatic aldehydes including isobutyraldehyde, 3-methyl-butyraldehyde, 2-ethylbutyraldehyde, phenylacetaldehyde, 2-phenyl-propionaldehyde, among others. These compounds were submitted to cytotoxic screening against three tumor cell lines presenting good to excellent cytotoxic profiles.
Highlights
The synthesis of 3-alkenyl-2-hydroxy-1,4-naphtho quinones has been a topic of permanent interest in Brazil and abroad.1,2 These compounds share structural features with natural lapachol (1), the most abundant quinone found in the core wood of various Bignoniaceae
N-butyraldehyde, valeraldehyde, heptanaldehyde, phenylacetaldehyde and hydrocynamaldehyde (3a-f), obtaining the corresponding products in low to modest yields (23-48%, Table 1). Hooker pointed that he was unable to obtain the condensation product from isobutyraldehyde, and from acetaldehyde he notes that a rapid consumption of the formed product was observed
The preliminary data found by the present method in the synthesis of norlapachol 4g showed a 95% yield, and resulted in patent filing
Summary
The synthesis of 3-alkenyl-2-hydroxy-1,4-naphtho quinones has been a topic of permanent interest in Brazil and abroad. These compounds share structural features with natural lapachol (1), the most abundant quinone found in the core wood of various Bignoniaceae. The synthesis of 3-alkenyl-2-hydroxy-1,4-naphtho quinones has been a topic of permanent interest in Brazil and abroad.. The synthesis of 3-alkenyl-2-hydroxy-1,4-naphtho quinones has been a topic of permanent interest in Brazil and abroad.1,2 These compounds share structural features with natural lapachol (1), the most abundant quinone found in the core wood of various Bignoniaceae. In 1936,4 published a systematic synthetic procedure for a series of 3-alkenyl-2-hydroxy1,4‐naphthoq uinones using lawsone (2) with suitable aliphatic aldehydes with hydrochloric acid as catalyst. N-butyraldehyde, valeraldehyde, heptanaldehyde, phenylacetaldehyde and hydrocynamaldehyde (3a-f), obtaining the corresponding products in low to modest yields (23-48%, Table 1). In 1986, Bock et al. published an update of this methodology (see Table 1) Hooker pointed that he was unable to obtain the condensation product from isobutyraldehyde, and from acetaldehyde he notes that a rapid consumption of the formed product was observed. Fifty years later, in 1986, Bock et al. published an update of this methodology (see Table 1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
