Here's a brief history on some tracks dissing Dre:
No Vaseline Was an attack on Dre and NWA after he left the band in 1991. Dre offered no effective response.
Shortly after Eazy E left, and him being the key player in the band marked the end of it.
Dre Day In 1993 Dre launched this attack on Eazy E with Snoop Dogg. Featuring a fake Eazy E (Sleazy E).
Real Muthaphuckkin G's (One of my favourite diss tracks of all time) was Eazy E's Response later in 1993; featuring appearances by members of the Crips, where he totally demolishes Dre. Dre and Snoop Dogg. Dre did not come up with a response before Eazy's death in 1995.
1995: Dre remained relevant by appearing in the smash hit Tupac song
California Love. Even though Dre had effectively been served by Eazy E and Ice Cube (all three of them were feuding with each other); a bigger feud began in 95 between the West and East Coast
2 of Amerika's Most WantedWith Tupac and Snoop Dogg re-enacting a scene from Scarface where Tony Montana fake calls Frank and then proceeds to have him killed; with Death Row playing Tony Montana's side, and Bad Bow playing Frank's side. Tupac had just got out of jail, and Snoop Dogg was on trial for murder conspiracy. Tupac had issues due to Biggie's associates shooting him five times; outlined in
Hit Em Up(probably the best diss track of all time), Dre at this point fled from Death Row where he would form Aftermath the following year. Dre disses can be found in several of Tupac's tracks from 96.
Dre FINALLY came back with the song
Forgot About Dre which he took many years to write; then associating himself with Eminem (who stole that show). It was a good song, but came WAY too late to be relevant to the early to mid 90's.
Fuck Dre Realist and Death Row diss on Dre in response. Rewriting an Eminem line "So what do you say to somebody you hate? Leave your body full of holes, let them chalk in tape, Mother fuck Snoop and N.W.A., Death Row could give a fuck about Dre."
Since this is an Eminem topic and I mentioned Pac:
Murder Murder - by Eminem with samples from Tupac, 1997.
Quitter - Eminem's cover of Tupac's Hit Em Up (starting at the 3 minute mark) directed towards Everlast, 2000.