Entertainment Music Chuck Negron was a founding member of the soul-rock sensations Three Dog Night, singing lead on such hits as One and Just an Old Fashioned Love Song and hollering the immortal opening line "Jeremiah was a bullfrog!" on the chart-topping Joy to the World . New York-born Negron and fellow vocalists Cory Wells and Danny Hutton were Los Angeles-based performers who began working together in the mid-1960s, originally called themselves Redwood and settled on Three Dog Night, Australian slang for frigid outback weather. Between 1969 and 1974, they were among the world’s most successful acts, with 18 top 20 singles and 12 albums certified gold for selling at least 500,000 copies. The trio of stars worked themselves into a raved-up, free-for-all passion, as if each singer were attempting to vault in front of the others. "The Kings of Oversing," the Village Voice would call them. Negron stood out for his drooping moustache, in contrast to his clean-shaven peers, and for his multi-octave tenor.…