He is also known for his 1982 work exploring the possibility of a connection between recreational use of amyl nitrite and an increased incidence of Kaposi's sarcoma in homosexual men.
After finding that 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide was useful for some reactions, Lawesson undertook a general survey of the reactivity of organic compounds with this reagent.
After Lawesson's death, Yousif has been working in Egypt and has been very active within the phosphorus sulfur chemical community.
[4] Prof T. B. Rauchfuss, who is in the United States did some very important work on Lawesson's reagent.
He did the 31P NMR experiment which proved that Lawesson's reagent could form the dithiophosphine ylides in solution.