Process for the preparation of benzanthrones
AssigneeBayer Aktiengesellschaft
InventorJosef Schroeder
Life of this patent
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Abstract
Process for the preparation of benzanthrones of the formula ##STR1## in which R designates alkyl or halogen and n represents 0, 1, 2 or 3, characterized in that anthraquinones of the formula ##STR2## in which R and n have the meaning indicated above, are reacted with acrolein or compounds from which acrolein can be formed under the reaction conditions, in the presence of phosphorus or phosphorus compounds having a reducing action, in relatively highly concentrated sulphuric acid at elevated temperature, and the reaction mixture is worked up in a manner which is in itself known to give the benzanthrones of the formula (I).
Claims8
Process for the preparation of benzanthrone of the formula ##STR6## in which R designates alkyl or halogen and
- n represents 0, 1, 2 or 3,
- which comprises contacting an anthraquinone of the formula ##STR7## in which R and n have the meaning indicated above, with acrolein or a compound from which acrolein is formed under the reaction conditions, in the presence of phosphorus or a phosphorus compound having a reducing action, in relatively highly concentrated sulphuric acid at elevated temperature, and working up the reaction mixture to give the benzanthrone of the formula (I).
Dependencies are inferred from the claim text.